Question

Part II – Descriptive epidemiology and hypothesis generation

Staff members from the local health department where the terminal stop of the bus route was located were invited to participate in the investigation.

In addition, physicians attending to the cases of botulism were asked to provide demographic and clinical information on their patients. (Table 1)

Question: Using the data presented in Table 1, first, briefly summarize the demographic and clinical information on these patients and second, draw an epidemic curve.

Table 1: Characteristics of cases of botulism, Montevideo, January 1994 Patient Work shift Onset of neuro- Age No.(years) Gender logic symptoms Symptoms 42 Morning blurred vision, double vision, drooping eyelids, upper and lower extremity weakness, respiratory difficulty, fatigue January 6 blurred vision, double vision, drooping eyelids, upper and lower extremity weakness 31 Morning January 5 23 blurred vision, drooping eyelids, upper extremity weakness, fatigue Morning January 9 46 Morning January 8 drooping eyelids, difficulty speaking blurred vision, double vision, drooping eyelids, difficulty speaking, respiratory difficulty 54 Morning January 5 49 blurred vision, drooping eyelids, difficulty speaking Morning January 10 blurred vision, double vision, drooping eyelids, upper and lower extremity weakness, respiratory difficulty, fatigue 31 Morning January 15 respiratory difficulty, fatigue, drooping eyelids Morning January 14 24 Morning January 12 drooping eyelids, fatigue *M-male gender

Answer 1

In this epidemic outbreak only male are affected. Total 9 male adult of age 23 to 54 years suffered from botulism between 5 january 1995 to 15 january 1995. Drooping of eyelid occurred in all 9 cases. Blurred vision experienced in 6 cases. Cases of age more than 45 years experienced difficulty in speaking and these are 3 in numbers. While upper and lower extremities weakness and fatigue were shown experienced by cases of age less than 45 years. 4 cases experienced upper and lower extremities weakness and 5 case experienced fatigue. Blurred vision and double are experienced by 6 and 4 cases respectively of all ages. Respiratory difficulty experienced by 3 cases.

Following is the epidemic curve