Infection Prevention and Control - Case Study Example

Name Professor Title Date [] 1) Epidemic Histogram Provision of the two epidemic curves at two-hour intervals aids in proper representation of data as it only happened within two days. The onset time and date of each of the 23 patients is indicated on the graph. 2) The arrow shows the median incubation period from the exposure time. Critical analysis of such a situation indicates that the cause of illness was linked to something consumed earlier as the first symptoms were noticed before lunch time. The median incubation period is some hours after lunch meaning it had got into the system of the individuals earlier. 3) Collected data indicates the propagation. The epidemic curve shows continuous exposure that is much pronounced after the lunch hour and ends the following day according to the collected data. According to the determined incubation period, the exposure is prolonged thus other victims display symptoms at a later time compared to the others. Complaint of the obvious symptoms of infection appears in the afternoon and evening. However, further analysis of the situation is vital to draw precise conclusion about the causative agent. 4) The case presented by the data qualifies to be an epidemic. It is a condition that involves a large group of people who are subjected to the pathological agent. Noticeable symptoms among affected individuals indicate they are suffering from the same thing or rather infected by bacteria or rather agent. Every individual in the camp had the same complaints that clearly indicate the source of the problem is among the food consumed. Furthermore, it occurs within a short period and affects almost the whole population in an unusual way thus qualifies to be termed as an epidemic. 5) Table showing ratio between male and female of the infected group Odds ratio = (17*4)/ (12*6) = 0.944 According to statistics on data relating to the whole population, there is no connection between gender and illness. The high percentage of male individuals showing symptoms of the illness is due to the general high population of male soldiers compared to the female soldiers. Also, the odds ratio adds emphasis on the proportionality aspect on the data. High population of the men means that they were exposed more to the causative agent compared to the females thus the high number of male individuals showing high levels of illness. 6) Table of relationship between age and illness Age Bracket 19-23 24-28 29-32 Ratio 52.2% 30.4% 17.4% Statistics on age distribution and infection indicate that there is no connection between illness and age of the individuals. People aged between 19 and 23 form the highest percentage of individuals. Therefore, exposure rate of the young individuals is high compared to the other age groups. Further proof of the preceded conclusion is taking a look at the age group 29-32. The age group forms the smallest portion of the population under consideration, and therefore they form the least portion of the people infected. Table showing age ratio within the whole group Age bracket 19-23 24-28 29-32 Ratio 47.4% 39.5% 13.1% 7) Table showing exposure to muddy water on 28th Muddy water exposure No muddy water exposure 11/23 12/23 Odds ration= (11*8)/ (12*8) =0.916 The proportion of individuals exposed to muddy water indicates there might be a relationship between illness and the exposure. The proportion of people who were exposed to the muddy water is almost half the number of people who got sick. Such information is not sufficient to draw conclusions that hold water concerning the matter. Furthermore, the relationship between time displaying symptoms shown on the histogram contradicts the opinion that the illness originated from exposure to muddy water. Further consideration of exposure condition is, therefore, vital in order to determine the causative agent and contain early enough to prevent further infection. 8) Table showing proportions of people who went for hiking and those who did not go for hiking 9) Went for hiking Did not go for hiking 15/23 8/23 Hiking ILL WELL Exposed 15 11 26 Not exposed 8 5 13 23 16 39 Odd ratio= (15*5)/ (11*8) =0.852 Attributable risk in this case is 57.7-61.5= -3.8 Attack rate= 23/46 =0.5 Contrary to the previous statistics on exposure to muddy water, higher percentage of people who went for hiking show signs of illness. Such statistics in conjunction with the median incubation time from the histogram show a high possibility that hiking could be the exposure point. Furthermore, Lyme disease has a longer incubation period explaining the symptoms after some time in the camp. Also, the symptoms displayed by the victims such as fever, nausea, and headache indicate a high possibility of Lyme disease. 10) Exposure-specific attack rate table with attributable risk and odds ratios RICE ILL WELL exposed 13 9 22 N/exposed 10 7 17 23 16 39 BEE ILL WELL exposed 12 8 20 n/exposed 11 8 19 23 16 39 POR ILL WELL Exposed 10 7 17 n/exposed 13 9 22 23 16 39 Exposed Not Exposed Att. R OR Item Ill total % Ill total % BBQ 13 23 56.5 10 16 62.5 -6 0.78 EGG 18 20 90 5 19 26.3 +63.7 25.2 RICE 13 22 59.1 10 17 58.8 +0.3 1.01 BEE 12 20 60 11 19 57.9 +2.1 1.09 HAM 11 19 57.9 12 20 60 -2.1 0.92 POR 10 17 58.8 13 22 59.1 -0.3 0.99 11) Att. R- Attributable Risks O.R- Odds Ratio Calculating the attack rate Attack Rate= 23/46 =0.5 11) symptom CRA DIA NAU VOM HEA FEV Percentage of ill personnel 91.3% 95.7% 56.5% 47.8% 56.5% 95.7% Number of persons displaying 22 24 13 14 15 23 The table clearly indicates that the most common symptom among the victims was diarrhea and fever. Abdominal cramps were displayed by most of the patients with the other symptoms averagely noticed among the group. 12) According to the presented data, the most likely VEHICLE for the infection is the eggs served on the 28th during training. 13) The probable median incubation period is 22hours. The period was achieved at by considering time since exposure to the first symptom by a victim within the group. 14) Pathogen Mode of transmission Symptom profile Incubation period Campylobacter Eating raw poultry, drinking contaminated water, unpasteurized milk, and contact with infected animals. Fever, cramping abdominal pains, nausea, vomiting, watery diarrhea which can be bloody. 1-7 days Clostridium perfringens Under cooked meat that is left out with favorable temperatures for the growth of bacteria Abdominal pain, stomach cramps, diarrhea, nausea 6-24 hours Salmonella Undercooked meat, poultry, eggs or egg products Nausea, vomiting, abdominal cramps, fever, diarrhea, headache, and blood in the stool. 6-48 hours Staphylococcus aureus Through contact with contaminated surfaces. Abscesses and cellulitis on the skin Days to years E. coli Contaminated water, undercooked meat, vegetables, and unpasteurized milk Diarrhea, abdominal cramps, nausea, vomiting 3-4 days Bacillus cereus Meat, milk, vegetables, and fish. Nausea, vomiting, abdominal cramps, and diarrhea. 1-16 hours a) Keen analysis of the collected data can aid in drawing conclusion that muddy water is not the cause of illness. It is because the percentage of people exposed is relatively low compared to those that got ill also looking at the possible bacteria and the incubation period of the pathogen associated with muddy water. b) Hiking is not the reason for the illness. The proportion of people who went hiking and did not get sick is high indicating this was not the source of the causative agent. c) Analysis of the food served the most probable causative agent is the BBQ Chicken and Egg salad sandwich. Statistics indicates that the majority of the individuals who had either of these meals suffered from the symptoms of salmonella infection. 15) After critical analysis of the presented data, determination of the causative agent was possible. Salmonella is the agent that caused the illness among the group. The main source of the bacteria was the eggs with a possibility that the BBQ chicken contributed to the same. The percentage of people who had eggs showed signs of infection relating to infection by Salmonella. Further evidence is seen in the group of people who did not get sick but showed various symptoms of gastrointestinal infection. Furthermore, the incubation period of salmonella infection coincides with the incubation period recorded after the collection of data. The odds ratio after consideration of those exposed on possible causative agents of salmonella supports the conclusion that the cause of illness among the people is salmonella. Consumption of other meals did not seem to have the effect on individuals as those who did not display any signs of illness. Furthermore, the incubation period of salmonella bacteria correspond to the median incubation period recorded. The symptoms displayed by a majority of the patients that is diarrhea, fever, and stomach cramps indicate that the illness was due to Salmonella. Improperly cooked eggs can be a source of salmonella bacteria infection. While serving a large group of people with eggs, there is a high possibility that the meal was served while it was not ready. Moreover, salmonella is mostly found in the gut of poultry animal thus improper cooking of poultry meat can lead to infection. Works Cited Büttner, Petra, and Reinhold Muller. Epidemiology. South Melbourne: Oxford UP, 2011. Print. Damani, Nizam. Manual of Infection Prevention and Control. Oxford: OUP Oxford, 2011. Print. Read More