Botulism in Argentina
Botulism is a condition that is rare but caused by bacterial toxins known as Clostridium botulinum, and the common forms of this bacterium are foodborne botulism that thrives in a little oxygen environment such as canned food. Wound botulism usually survives in cuts and produces dangerous toxins. Lastly, there is infant botulism where the spores of the adult bacteria come in contact with an infant generally between 2 and eight months and the spores grow in the baby’s intestinal tract (Shrivastava et al. 17).
Question 1
The major concerns raised in both of these cases are the symptoms presented by the patients including double vision, drooping eyelids, respiratory problems and difficulty in swallowing. The other concern would be to verify if the symptoms are contagious or not and evaluate how long it took before the symptoms started presenting themselves (Bennett et al., 15). It is important to ask some questions such as- was there anything out of the ordinary the patients did before presenting with the symptoms? Does the condition only affect men and why? What places do they have in common? Do they have any family and how is there condition? Since both patient’s blood work did not have results establishment of the cause of the infection would be a major concern. It is done by interviewing the patients further in attempts of trying to establish what could have been the cause of the condition (O’Sullivan et al. 16).
Question 2
Mapping is the best approach in such cases, and therefore, after interviewing the patients, it would be clear the common place where the patients had been and what they did. Following this, it would be necessary to visit the place and survey, for example, it is essential to get the number of people who usually attend the restaurant which is the most likely commonplace in such a case. If the patients remember the exact date that they went to the restaurant, it was appropriate to get the number of people who went there on that particular day. Finally, take samples and submit them for testing, whereby, if it’s a restaurant the samples of food, water, and other drinks are taken for analysis. It would help determine the source of the infection and the approximate number of possibly infected people (Bennett et al. 14).
Question 3A
The key points to include during the press release of such a condition include informing the press about the situation (Rim et al. 10). The nature of the condition and how it can be acquired should be realized to prevent rumors and provide relevant information about the signs and symptoms and encourage those with similar symptoms to visit the nearest health facility. Provide information on preventive and control measures which include it include warning the patients against visiting certain suspected areas.
Question 3B
The people to be included during the press release is a team that comprises of the physician, who is dealing with the cases a nurse that gives a better picture of the signs and symptoms, a public health practitioner and a representative from the hospital’s administration (Rim et al. 89). The team should select a spokesperson that will be responsible for the delivery of the information. However, the press release cannot be made without a public health officer or a public health nurse since people must be notified before the press release.
Question 4
The press release should not have mentioned the names of the infected persons and the physician too (Rim et al. 12). Most patients value their privacy to avoid stigmatization from the public. The press release is also creating panic in public by stating that the officials are worried and that other persons may be infected since the source is not known. Instead, the release should have stated they are working to manage the situation. The press release also should have mentioned how the infection can be prevented. However, the press release has given detailed information on the symptoms and the appropriate steps to be taken if one is suspected of having the infection.
Question 5
Control measures at this point would be necessary to stop the spreading of the infection. Take samples of food and drinks from home for testing and establish if it is the real source of the infection. If the tests are positive, the home should be cl, used and the owners relocated until the infection clears (Rutala et al. 8). The drivers should also be discouraged from taking anything from the home to prevent new infections from rising. Also, all drivers that work on that route should visit the hospital for a check-up.
Question 6 A
It is determined that these cases are a point-source outbreak. The victims are all male presenting similar symptoms that are, blurred vision, drooping eyelids, upper and lower extremities weakness, fatigue and respiratory difficulty were the typical symptoms. Two patients were reported to have speaking difficulty.
Epidemic Curve
Source (Bennett et al. 210).
Question 6B
The most likely period of exposure to these bacteria was the 4th of January. Most patients started reporting symptoms on the 5th and the incubation period of the bacteria is between 18- 36 hours, and in some circumstances, it can be as soon as 6 hours.
Question 7
The choice of hypothesis study, in this case, is a retrospective cohort study. This is the appropriate study because this case involves drivers who are a small and well-defined population. Each driver will be contacted to determine their possible exposure to the food in the home at the station terminus. The data will be collected and later analyzed and determined if the hypothesis is correct.
Question 8
What did they eat that day? Did they take anything to eat or drink from the home? At what time did they leave their ship, ft? Were they aware that the home had a problem? What is the general sanitation of the home? Have they ever eaten in the home? What did they eat and did they have any problems later?
Question 9
The first step in designing a questionnaire is to establish the purpose. In this case, it is to determine the source of the bacterial infection. Is the home at the bus the only source or is there any other. The second step is to understand the use of the collected data. In this case, the data will be used to compare infected drivers and those that are not. The next step is the selection of the target group. In this case, the target group is drivers and those in the morning shift. The fourth step is the selection of an appropriate method. In this case, one on one interview would be appropriate, but one can go with the most convenient method that the drivers would prefer. Section of the questions is the next step (Sullivan-Bolyai et al. 17). The questions can be either qualitative or quantitative. Quantitative questions, in this case, would be used to establish the exact number of drivers that visit the home in a day. Qualitative questions will set the sanitation standards of the home at the bus terminus. The next step is the writing of the questions. The questions should be in simple language and should be written in succinctly as possible. The questions should also be arranged. The arrangement should be thought out starting with simple questions that are not too personal. The questions should also be mixed from yes/no response questions to open-response questions. This will help keep the respondent interested (Sullivan-Bolyai et al. 9). Finally, the questionnaire should be tested either on friends, family or colleagues. It helps identify unclear questions awkward questions and any other mistakes that one could not notice on their own.
Question 10
What is their age? What is their level of Education? What is their favorite meal on the menu? How many times do they eat at the place in a day?
Question 11
The process is costly since the personnel will demand payment. There is also no way of telling if the respondent is truthful (Sullivan-Bolyai et al. 16). The quality of data received usually depends on the ability of the interviewer some individuals have a natural ability to collect data well during an interview while some do not.
Question 11
Odds of exposure (cases) = number of cases with exposure/Number of cases without the exposure
= 27/16=1.67
Odds of exposure (controls) = number of controls with exposure/ number of controls without exposure
= 45/75= 0.6
Odds ratio= odds exposure cases/ odds exposure controls
= 1.67/0.6= 2.8
Question 13
The figure shows that the odds of exposure among the case are greater than the exposure among controls. This means that those who ate the food at the place are at risk of getting the infection. Information on where the foods are bought from would shed some light on the source of the contamination.
Question 14
Assessment of the availability of the food in the firm. How the food is placed stored before being sold. Who has access to the food before it is sold for consumption? Some of the equipment required are gumboots, gloves, masks and containers of collecting samples (Vandeputte et al. 7).
Question 15
The food may not have been stored in a refrigerator instead it was just wrapped in plastic bags making it be at risk of contamination. It might have been stored in a dark room that was humid increasing the chances of disease. While caring, they may not be using any protective gear like gloves rather it was just carried on bear hand (Vandeputte et al. 13). The facility also did not have any hand washing point to minimize any chances of contamination.
Question 16
The control measures to be taken at this time would be to immediately shut down the processor until they meet the suitable sanitation requirements for running a food processing plant. The major difficulty may be that the owners of the processer might not comply and blame the home for causing the outbreak. However, the home should also be shut down until they meet the requirements too (Rutala et al. 4)
Question 17
The long-term intervention would be to enforce strict policies on food processing firms. They should meet a certain standard before being issued with a license that will allow them to start processing and distribution of food products in the area.
Question 18
The rationale is to reduce or eradicate cases of botulism in the country which is achievable through the distribution of the antitoxin.
Question 19
Monitoring will entail random visits to health centers all over the country and check on any reported cases of botulism. If the cases have reduced, it means that the system is working but if not another strategy will have to be put in place.
Case 2
Norovirus in Vermont
Norovirus is a type of virus that causes gastroenteritis which is a gut infection that is usually characterized by vomiting and diarrhea. Dehydration is the main risk when one is infected. The virus is highly contagious, and it is mainly spread through contaminated water or food, in addition, close contact with an infected person can also spread the virus (Ahmed 3). The symptoms usually begin 12-48 hours after exposure to the virus (Ahmed 3). However, norovirus symptoms last between one to three days and most people recover fully, but others do not get better. Norovirus infection often occurs in crowded places such as nursing homes, hospitals, schools, and child care centers.
Question 1
When did the vomiting start? What triggered the vomiting? Did they have something to eat before the vomiting started? Are the children in school? The priority in this situation is to establish what the children have in common, for example, if its school or a favorite food place would be a probable source of the infection (Marsh 5).
Question 2
Etiological agents are infectious agents, in this case, are the three children in the neighborhood. Although they do not play together, they came into contact with each other during a birthday party, and it is most likely where the patient acquired the infection (Marsh 3). The party is the common place where the children could have easily acquired the infection and spread it. The children also share the same school, and this virus is highly prevalent in crowded places such as learning institutions.
Question 3
Take samples of what was taken by the children while at the party if possible and sample from the pool and test for the virus while all those who attended the party are to be contacted. (Marsh 8).The club management is also to be contacted and questioned whether there are any complaints about the pool. Other additional information that would be necessary include understanding where the cake, ice cream and anything consumed in the party was purchased.
Question 4
The swim club manager should be informed about the cases and the condition that the children are in after the party that was held there. It can be done by making arrangements on meeting with the manager and convince him/her to allow investigations to go on to establish the source of infection. It could help prevent the spreading of the infection.
Question 5
Children started vomiting and diarrhea after they attended a birthday party held at a swimming club on February 1st. also, the manager of the swimming club also said he had received reports of illness among other people who had used that swimming pool during that period. Those who accessed the pool between January 27th and the 1st of February were contacted (Streiner and Jan Kottner 6). It was established that 21 people visited the pool and they had reported to the health center with the symptoms. The 90% of them were vomiting, 81% vomiting, 67% had abdominal cramps, 48% had diarrhea and fever (Streiner and Jan Kottner 7). The symptoms began between 8-62 hours after exposure to the swim club. The earlier suspicions that the party could have been among the source of the infection was right. The swimming pool is most likely to be the source since those who shared the pool apart from the children also had similar symptoms. The cases were clustered across the demographic characteristics especially for those who had accessed the pool. Infant mothers who had swimming classes and children who attended the party were the ones affected. The time course of the outbreak was between 29th of January to the 3rd of February.
Question 6
A retrospective cohort study is the appropriate method of approach in this case because it involves a private swimming pool that in most cases usually has a small population. Investigators will have to contact each person who visited the swimming club on those particular dates and determine if they had accessed the swimming pool and it should be noted if they later became ill or not (Musa et al. 10). After collection of this data from each person that was at the swim club during those particular dates, the rate of infection is calculated. The infection rate of those who accessed the swimming pool and those that did not. If the rate of infection is high among those who accessed the pool compared to those who did not, then the pool is the definite source of the disease.
Question 7
To prevent or reduce contamination in swimming pools, controlling the clarity of water measures are taken (Arnold and Kathleen 13). It involves treating the water adequately through filtration and coagulation. However, controlling of pathogens in the pool is done through recycling of water in the pool through treatment (Anderson et al.18). The water is typically filtered and disinfected during this process. In addition, application of chemical disinfectants is made regularly to inactivate microorganisms that might be introduced to the pool by, for instance, bathers. Some pools cannot be treated, and in such cases, they need special management. However, not all infectious are killed by the disinfectants, and pool treatment by removal is slow therefore it is important to minimize cases of accidental fecal release and vomits. When these accidents occur, the swimming pool attendants are required to respond effectively to minimize the introduction of microorganisms in the swimming pool (Arnold and Kathleen 13).
Furthermore, disinfecting agents are also controlled by dilution to ensure that they are in safe quantities for swimmers. It is routine in some swimming pools for one to shower before swimming (Anderson et al. 20). Pre-swim showering removes traces of urine, sweat, cosmetics, fecal matter and other substances that can potentially contaminate the water. Pre-swim hygiene makes the pool clean and easier to disinfect thus requiring a little amount of sanitizing chemicals making it even more pleasant for one to swim (Anderson et al. 20). Post-swim showers are also necessary especially those that are private and allow nude showering. They should be located on the route from changing rooms to the pool. Post-swim showering also helps in the removal of any microbes that one might have acquired from the pool while swimming.
Question 8
Turnover rate is the amount of time taken in hours by a swimming pools circulation system to circulate a specific number of gallons equal to the total volume of the pool (Anderson et al. 24). The minimum recommendation of a pools turnover rate is 12hours, which means that all water in the pool should have been cleaned and filtered within 12 hours after the circulatory pump is turned on (Anderson et al. 24). The purpose of circulating water in a pool is to filter and ensure that the water is clean and conducive for swimming.
Different swimming pools have different turnover rates, examples of these facilities are wave pools that require having a minimum turnover rate of 2 hours (Anderson et al. 24). The difference in turnover rates of different pools is due to the difference in size especially depth and the type of the pool. However, different states have different turnover rates for their pools (Anderson et al. 30). For instance, in Montana, a spa pool is required to have a turnover rate of 30 minutes wading pools are required to have a minimum turnover rate of 1 hour.
Question 9
When chlorine is added to water, it breaks down and forms hypochlorous acid (HOCL) and hypochlorite ion (OCl-) (van Veldhoven et al. 6). These chemicals kill the bacteria and microorganisms by attacking their lipid cell wall. They also destroy the structures and enzymes found in the cell rendering them harmless and oxidized (van Veldhoven et al. 8). The effectiveness of chlorine as a disinfectant is influenced mainly by its concentration as it is being applied in the pool. There are thresholds and maximum levels set for the concentration of chlorine so that it can be useful when applied in a pool, however, if the concentration is too high chorine might also affect the skin of those swimming. Swimming pools are set to have a maximum level of 1.5mg/l of chlorine and a minimum of 0.5 mg/l (Rachmadi et al. 9).
Question 10
The main tests performed in a swimming pool using the test kits are; pH, which should be between 7.2-7.8 to ensure that someone’s skin is not corroded as they swim. Secondly, chlorine levels which should be at1.0-2.0, a total alkalinity of the pool which should be range from 80-120 ppm. Calcium hardness is also tested, and it should be between 200 and 400 ppm (Rachmadi et al. 12). Cyanuric acid levels are also tested and should be ranging from 20-50 ppm and finally the total amount of dissolved solids especially for outdoor swimming pools, and they should be below 5000 ppm (Rachmadi et al. 12). Samples from the pool can be collected using test tubes or small water containers for further analysis and testing
Question 11
Pool cloudiness can be due to failure in the swimming pools filtration system. However, the sample that showed that chlorine levels were 1.5 ppm and an excess of 0.5 ppm indicates chlorine levels were higher than the recommended levels (Lempart et al. 10). High level of chlorine in the water was the reason why the pH to be at 6.8. Recommended pH levels in a pool should range from 7.2-7.8 meaning that the water is neutral. A pH of 6.8 indicates that the water in the pool is slightly acidic therefore not suitable for swimming. Excess chlorination in swimming pool water causes the swimmers to feel slight irritation on the eyes and skin as they swim. In addition, low pH in the water in a pool is corrosive (Lempart et al. 12). It is felt by swimmers as the water usually strings their nasal passages and eyes.
Question 12
The duration is taken by each person while swimming is the major risk factor. Those who took longer the duration of time while swimming is at the greatest risk exposure to the pathogens. The accidental taking of the pool water while swimming is also a risk factor (Adam et al. 7). Taking a shower before and after swimming is also important as it can help establish those who tried to reduce their risk of being infected.
Question 13
The results indicate that not all of those who were exposed to the swimming pool got sick. However, there are those who did not access the swimming pool and still had the symptoms. The highest risk of exposure to the facility was 59%, and most of them were well but also recorded the highest number of those who got sick. These results, therefore, indicate that those who ate at the facility acquired the infection more compared to those who swam or accidentally took water while swimming.
Question 14
From the results, it is definite that eating or drinking from the club was a risk factor. To explore these findings, staff who serve at the facility should be interviewed and establish the source of the food and drinks served at the facility. Also, the facility should also be assessed if it is fit for consumption of food.
Question 15
The pool staff should be upgraded and employ more experienced and educated pool attendants. The facility’s management should ensure that the staffs have standard operating producers that can deal with pool emergency situations such as over chlorination of pool water. In addition, the facility should also ensure that swimmers shower before getting in the pool for the reduction of chances of pool infection (Adam et al. 34). Regular pool tests should be done, and the results kept well for future reference. Finally, the facility should ensure that the foods and drinks that are served are of good quality without any form of contamination.
Question 16
The incidents differ because in diarrheal cases the fecal matter is at risk of easily infiltrating through the filtration system and causing more damage to other systems connected to the same pool. However, stool incidents are easier to deal with since stool won’t be allowed to pass through the filters.
Question 17
Information to be shared with the swim club members is that they should embrace pre-swim hygiene. Shower before and after getting into the pool and they should also be careful with what they drink or eat while at the facility.
Case 3
Epidemiology
Exercise 1.1
The given information would help epidemiologists to shift and mainly focus on the particular group of individuals in the community. It will help epidemiologists establish why this specific group is majorly at risk (Beyrer et al. 6). Epidemiologists will also be able to know what the risk factors are that make this particular group more susceptible to the virus. The knowledge of this will aid in the development of effective treatment and preventive measures in the population.
Individual decisions will also be affected by the availability of this information. Availability of this information will make people make informed choices about their sexual partners and spouses. People will also be able to take the correct preventive and responsible measures during sex.
The information would also help researchers focus on that particular group. Take blood samples and try to establish the cause of the disease (Beyrer et al. 7). The data also helps in determining why that individual is highly at risk of getting the infection. Determination of purpose is vital so that relevant preventive measures can be developed.
Exercise 1.2
Patient’s ID Name Classification
1 Abels possible case
2 Baker probable case
3 Corey probable case
4 Dale suspect case
5 Ring, not a case
Exercise 1.3
- a) Coronary angiography and echocardiography are the primary techniques used in the diagnosis of cardiovascular disease (Shankar-Hari et al. 8). A patient with Kawasaki disease usually has heart rhythm complication and coronary artery abnormalities. By doing these tests, it helps rule out or establish the existence of the illness (Rigante et al. 5). Urinary tests help rule out the life of other diseases. Blood tests are also done during diagnosis, and it helps in ruling out other diseases while the presences of anemia, elevated white blood cell count and inflammation indicates that the patient has Kawasaki disease. Treatment goals of Kawasaki disease is a reduction of inflammation, fever, and prevention of heart damage. Gamma globulin infusion helps reduce the risks of coronary artery complications. Aspirin is used for the treatment of inflammation. It also helps reduce joint pain and inflammation and reduce fever (Rigante et al. 6). However, taking aspirin has been linked to the development of Reye’s syndrome in children.
- b) Tracking the occurrence of the disease will help establish the risk factors and those who are highly at risk of getting the disease. Also, monitoring the happenings of this condition will aid in the establishment of proper preventive measures to reduce its prevalence.
- c) The case definition would help researchers establish the cause of the disease especially now that there are no laboratory tests for the condition. The case definition also states the symptoms and their onset period (Rigante et al.10). The information will help researchers in the identification of the patients with the condition, take samples and do relevant research.
Exercise 1.4
There have been several cases of the unknown disease reported since February to October. In February and March, less than 50 cases were reported while in April 130 cases were reported. May and June had the highest reports which were 320 and 440 respectively. 150 cases were published in July, and 60 cases were reported in August. September recorded 30 cases, and 20 cases were reported in October (Chan 15). Surveys were done to investigate the several incidences of the disease. The first One was done in 24 villages focusing on age and sex. The highest cases were reported to be in both males and females aged between 5-9 years in the town. Also, the disease was also said to affect mostly married women between the ages of 16-29 years. However, most cases were also reported in individuals with level stratum economic levels.
Exercise 1.5
Observational/cohort study
Experimental study
Observational/ case-control study
Not an epidemiologic study (Pastor-Satorras et al. 13)
Exercise 1.6
Agent
It Refers to the infectious organisms such as a bacterium, virus parasite or any other microbe. In this case is the Human Immunodeficiency Virus (HIV) (Chan 3).
Host
Host factors are factors that affect an individual’s susceptibility to a causative agent. These factors include race, age, sex, behavior, and social, economic status. For HIV some of the host factors include gay and bisexual men, injection drug users, transgender women who have sex without protection (Vermund 9). Involvement in risky behavior such as sharing of needles and sharp objects and having of anal or vaginal sex without protection (Centers for Disease Control 3).
Environmental factors
These are extrinsic that affect the causative agent and increases the risk or provides the opportunity for infection. Environmental factors are such as climate and physical surroundings of the host. Environmental factors also include biological factors such as transmitting factors like insects and socioeconomic factors like sanitation crowding and accessibility to health services. In HIV prevalence some of the environmental factors are such as poverty (Vermund 12). Research indicates that the highest number of injection drug users is in suburban residents.
- b) The risk factors are sufficient causes for the condition. Adequate reasons are a minimum set of events and situations that eventually lead to the development of the disease. Necessary causes are factors that are a must for the development of the disease. In this case, the risk factors are not a must for the development of hypertension. Component causes for a disease is an event that is required for the development of the disease.
Exercise 1.7
Yellow Fever
Reservoirs:
Aedes aegyptui mosquitoes and man are the primary reservoir for the virus. In forest areas, vertebrates apart from a man such as monkeys and marsupials are the primary reservoirs. Maintenance of the infection in the mosquitoes is contributed by transovarial transmission in the mosquitoes (Monath, Thomas and Pedro 3). However, man does not play an essential role in the transmission of jungle yellow fever or maintenance of the virus.
Portals of Exit
The exit of yellow fever virus is through all body surfaces or the bloodstream. However vertical transmission can take place in the ovum, through the placenta during childbirth or colostrums milk (Monath, Thomas and Pedro 5). Besides, the mode of exit of the virus is not necessarily the same as the same as the entry points.
Mode of Transmission
The primary way of transmission in both urban and certain rural areas is by bites of Aedes aegypti mosquitoes. In South America, the sting of several species of mosquitoes from the forest especially of the genus Haemagogus transmits the virus (Monath, Thomas and Pedro 6). In East Africa the principal vector in monkey population is Ae. Africanus while Ae.simpsoni and Ae.bromeliae are the primary vectors of the transit of the virus from monkey to man in semi-domestic settings.
Portals of Entry
Port of entry of this virus is through a bite by a mosquito on the body surface into the bloodstream (Monath, Thomas and Pedro 7).
Factors in Host Susceptibility
Traveling to regions where yellow fever is common is the major risk factor of infection in this condition (Monath, Thomas and Pedro 8). However, this risk can be reduced through vaccination.
Viral Hepatitis A
Reservoirs
Man is the primary reservoir. However, chimpanzees are also reservoirs although they are rare (Stanaway 4).
Port of Exit
The virus exists the body mainly through stool and other body fluids such as urine (Stanaway et al. 5)
Mode of Transmission
The primary way of transmission is through the fecal-oral route from person to person. The infectious virus is in feces which contaminate food that is later consumed by a man causing infection (Stanaway et al. 7). However, direct transmission occurs among homosexuals especially males.
Ports of Entry
The common source of the outbreak is the consumption of contaminated food and water by infected food handlers or food from contaminated sources such as sewerages (Stanaway et al. 9).
Factors in Host Susceptibility
Lack of safe water, poor hygiene such as poor hand washing habits and poor sanitation are the fundamental causes of this infection (Stanaway et al. 11). However, homologous immunity acquired after recovery from hepatitis A lasts for life.
Exercise 1.8
Point source
Intermittent or continuous
Propagated (Chan 21).
Case 5
Epidemiology
- coli fully known as Escherichia coli is a bacterial type that survives in the intestines as normal flora. It is also found in the gut of several animals such as cows. Most types of these bacteria are harmless and aid in the digestion process. However, at times it can cause diarrhea when one takes food or water contaminated by the bacteria (Tarr et al. 3)Eating of contaminated meat, untreated milk, fresh fruits, and vegetables or those that are tainted by water are major causes of infection.
Question 1A
Increased consumption of beef, which may have been contaminated among the resident is the primary reason. A weakened immune system among those who reported could also have been the case (Tarr et al. 3). In addition exposure to contaminated vegetables or water could also be a reason for increased reports (Szklo, Moyses, and Javier 90).
Question 1B
The type of food mostly consumed by the residents before they started having the symptoms would help in narrowing down to the specific food (Friis et al., 6). The sources of vegetables and beef among residents will help in establishing the source. If it’s a market how is the sanitation of the market? How the food is processed is necessary for establishing where the source of contamination might be. Information about the source of water would also play a big role.
Question 2
2and 3 are similar. 4 and six are similar while 7 and nine are also similar (Muñoz-Atienza et al. 9).
Question 3
Advantages
It is efficient for this disease considering that is rare with a relatively long latency period between infection and manifestation of symptoms.
It is less time consuming since it is short and precise
It is helpful in studying the dynamic population in which it is difficult to follow –up as it is in this case.
Disadvantages
There is insufficient information.
It does not allow calculation of incidence (absolute risk).
They are selection bias since not all cases are included.
Information on is usually observation bias as some symptoms are likely not have been included.
Would have included more symptoms state the exact number of patients who reported to the facility and what symptoms they had. In addition, mentioning how long the laboratory cultures were done would be significant (Holtfreter et al. 18).
Question 4
In Michigan, those who are most affected by the bacteria are females that are above the age of 60 years while the least cases are reported in both male and female who are between 0-9 years. However, in the whole country, the most cases are reported both males and females aged between 1-9 years while the least cases are reported among females aged between 40-49 years. In Michigan, females seem to be most affected by the bacteria while in the whole country, those most affected are males.
Question 5
What is their age?
What are their occupation and their level of education?
When did the symptoms start?
For how long have they had the symptoms?
What did they have before experiencing the symptoms?
What counties exactly have they been to?
What is their frequently prepared food?
Where do they buy their food?
What is their source of water?
Do they eat in any restaurants? If yes which one and how frequent? (Brace 10)
Question 6
#Practical
Question 7
38 cases were reported with patients complaining of having diarrhea, abdominal cramps that began between 15th of June and15th of July. After interviewing the patients, it was established that the patients mostly consumed lettuce and alfalfa sprouts a week before they started having the symptoms. According to the latency period of the bacteria, the leading hypothesis is that vegetables are the source of the infective bacteria. The market where the vegetables are purchased is likely to be a contaminant or the farm where the vegetables are bought from (Szklo et al., 7).
Question 8A
Controls in this study would be those who have had the vegetables and did not show symptoms of the condition across all ages. The other case-control would be those who did not have the vegetables but are showing symptoms of the illness (Szklo et al., 15).
Question 8B
Yes to determine the distribution of the risk factors among people at a particular age group. This would be helpful during the development of control and preventive measures since appropriate emphasis would be put on the most vulnerable age group (Szklo et al., 16).
Question 9
Controls are used to determine if a specific exposure is associated with a particular outcome. In this case, it is used to establish if the vegetables are the source of the bacteria. What happens first is that the case is identified that is the group which has the known outcomes. In this case, it is the patients at the hospital. The controls are a group that is free of the symptoms. In this case, it would be those who had the vegetables but are not showing any symptoms or those who have the symptoms but did not have the vegetable (Friis et al., 412). Then a comparison is made between the two cases and the frequency of their exposure to the suspected risk. Several methods might be used. They include cohort study, case-control study, and cross-sectional study.
A cohort study has the following advantages; it facilitates studying exposures that are rare. This study allows examination of various effects of a single exposure during the study (Friis et al., 413). It allows calculation of incidences of exposure and finally the study is not selection bias. Some of its disadvantages are; the method is expensive, and it is also time-consuming as it involves a lot of logistics.
A case-control study has several advantages including, it is an effective method while studying diseases that are rare. It is also less time consuming and it is less costly. Disadvantages include, this design is subject to selection bias. It also does not allow the calculation of incidences. This study also has an observational bias (Friis et al., 414).
The cross-sectional study compares data gathered for a specific point in time. Its advantages are, it is used to prove or disapprove a hypothesis. It is cheap and less time-consuming. This study also captures a specific point at a one particular time. Many outcomes and findings can be analyzed through this study. Its disadvantages include; this method cannot be used to determine the cause and its effect. It can also not be used to analyze behavior over a particular duration of time (Friis et al., 415).
Question 10
For the risk factors would be from 6th to 8th of July. The controls it would be from 6th of July to 7th of June (Friis et al., 54).
Question 11
Alfalfa sprouts are the most likely source of the infection. 56% is a great percentage that was reported ill after eating it. Samples need to be taken from the source, and a lab culture has done to establish if they are contaminated. The plants are likely being grown near a contaminated area, or the handlers of the vegetables are careless (Szklo et al., 8).
Question 12
The people might have had another vegetable that is closely grown to alfalfa sprout, or they might have had water that is contaminated. The patients also might be having a weakened or low immunity. The patients might also be having low acid levels in the stomach that protect the stomach walls from bacteria. In addition, most cases of this condition are usually reported in June throughout September in the United States (Allard et al., 31). The reasons for this are not known.
Question 13
The patients should stop taking alfalfa sprouts immediately. Those growing them in their homes should stop for a while too. The vegetable market should also be shut down or where the shoots and seeds are bought from. Samples should be taken, and a culture has done to establish if the seeds and vegetables are contaminated with the bacteria (Muñoz-Atienza et al. 54). In addition, the market or stores that sell this vegetable and seeds should be investigated especially about their sanitation standards. The farms where the vegetable is grown should also be examined through the taking of samples of the vegetables and the sources of water to the farm. The water source for the whole community should also be investigated.
Question 14
Traceback investigations usually take place when the epidemiologic evidence points at only one food product and all hazards analysis indicate that there are no other contributing factors to the outbreak (Allard et al., 84). The severity of the infection is also considered, the scope of the epidemic, availability of necessary resources to carry out the investigation and the availability of records that were used during shipping of the product. In this case, a traceback investigation would be necessary to prevent future occurrences.
Question15
Which store was the alfalfa sprouts bought from? The store should also have records of when they bought the sprouts with their seeds and where they bought it from. The store should also explain clearly the shipment process and how the vegetables are handled before they sold for consumption (Resh 202). The store should also establish if they have one supplier or several and provide the necessary information about them.
Question 16
In Michigan facility, A is the main source of the infection. It is because the facility used seed lots that came from Idaho and a similar case had been reported earlier in Virginia. The sprouting company in Virginia was sprouting mainly using the same lot of seeds, and similar outcomes were reported later. Through this, it is clear that facility A that uses seeds from Idaho to sprout their alfalfa is the primary source of the infection in Michigan.
Question 17
The location of the farm should be considered. Is the vegetable farm located near an animal farm? The proximity of the animal farm especially cows to where the vegetables are being grown could be a source of contamination. How the animal wastes are being handled on the farm is also necessary to be investigated. The seed processing plant should also be assessed and any risks identified (Resh 301). The source of water to the farm should be considered since during processing and growing process the water is used.
Question 18
The farm should be moved somewhere else far from where wastes from the animal farm can contaminate it. The deer refuge should be fenced to prevent deer from entering the vegetable farms. The seed cleaning processes should be made up to date, and they should not only rely on water. Further processing should also be done such as decontamination to ensure that the seeds are safe and free of bacteria (Holtfreter et al., 46). However, for the time being, seed production in the farm should be stopped until the required standards are met for the plan to continue processing.
Question 19
No matter the outbreak people are still going to consume the sprouts. Therefore the best method of intervention is consumer education. Educating the consumer on safe ways of sprouting alfalfa will go a long way even protecting the future generation since information can be passed from mother to child (Friis et al. 447). One of how consumers can be educated about sprout is by the publication of newspaper articles, announcements on the TVs or radio. Empowering of any community about prevention of certain illnesses through education has proven to be successful over the years.
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