Unexpected Deaths in Panama

Centers for Disease Control and Prevention and Kenya Field Epidemiology and Laboratory Training Program Case Studies in Applied Epidemiology No. 122-613

Acute Unexplained Jaundice in Rural Kenya Participant's Guide

Learning Objectives

After completing this case study, the participant should be able to:

 Draw an epidemic curve,

 Discuss the steps of an outbreak investigation,

 Develop and apply a case definition for a field investigation,

 Discuss the possible sources of controls for a case-control study,

 Describe the relationship among epidemiologic, laboratory, and environmental components of a field investigation.

This case study is based on an investigation conducted in 2004 by the first cohort of residents in Kenya’s Field Epidemiology and Laboratory Training Program (FELTP), with assistance from CDC-Atlanta and many other organizations.

This case study was developed by Richard Dicker in 2012 for the Kenya FELTP, with review and input from Eduardo Azziz-Baumgartner, Lauren Lewis, and Patrick Nguku. CDC / Kenya FELTP, 2013: Acute Jaundice in Kenya (122-613) — Participant’s Guide Page 2

Part I

In mid-May 2004, the District Medical Officer of Map of Kenya Health (DMOH) in Makueni District, Eastern Province, contacted the Kenya Ministry of Health. Twenty children had died of hepatitis in Masongaleni Location in Kibwezi Division in the past week. The children were between the ages of 5 to 10 years. Symptoms included fever and jaundice of the eyes, and distended abdomen. The DMOH speculated that the cause could be hepatitis B, but no tests were available.

The DMOH also reported that isolated cases of a similar disease had occurred in neighboring Makindu Division, and in Kitui District, just north of Makueni District. Makueni The DMOH warned local residents against self- District treating their illness using local herbs and leaves, saying this could potentially worsen the course of disease and delay treatment.

Question 1: What causes would you include in your differential diagnosis of these cases of hepatitis?

CDC / Kenya FELTP, 2013: Acute Jaundice in Kenya (122-613) — Participant’s Guide Page 3

Question 2: Would you call these cases an outbreak?

The DMOH also contacted agricultural officials. first cohort that year. CDC-Kenya, CDC-Atlanta, During past periods of drought and food scarcity, and the World Health Organization were also occasional outbreaks of similar illness had invited to participate in the outbreak occurred that were attributable to consumption investigation and control efforts. of mycotoxin-contaminated food grains and legumes. Agricultural officials sent samples of The KFELTP residents reviewed the maize, beans and flour to the laboratory for epidemiology of aflatoxicosis: testing. Aflatoxins are naturally occurring mycotoxins The following day, officials attributed the produced by Aspergillus species fungi that grow outbreak to aflatoxicosis (aflatoxin poisoning) on a wide variety of grains and nuts, particularly from eating contaminated maize. during development of grain seeds and during storage under conditions of high moisture and "We took samples of maize and maize meal temperature. from the affected villages for analysis, and aflatoxins were detected," a health officer Aflatoxicosis generally begins with anorexia, confirmed [ProMed 14 May 2004]. Some malaise, and low-grade fever, and can progress samples had concentrations of aflatoxin B1 as to potential fatal acute hepatitis with vomiting, high as 4,400 ppb, which was 220 times greater abdominal pain, pulmonary edema, convulsions, than the 20 ppb limit recommended by Kenyan coma, and death. authorities. However, the origin of the contaminated maize was uncertain. Because the Chronic dietary exposure to aflatoxins has been area had been experiencing grain shortages, found to be a risk factor for hepatocellular maize had been brought in from other areas of carcinoma, particularly in areas were hepatitis B the country. virus infection is endemic.

Local health officials noted that new cases of A previous outbreak of aflatoxicosis had occurre hepatic failure were continuing to occur. They d in Meru District of Central Province in Kenya in also had heard reports of similar cases in other 2001. In that outbreak, at least 12 people died a districts and reports of deaths of livestock and nd 12 others were hospitalized. Half of the maiz poultry that had eaten feed made with maize. e samples collected from local food kiosks and markets tested positive for aflatoxins. Health offi The Kenya Ministry of Health, concerned with cials then seized and destroyed more than 13,23 the magnitude and seriousness of this outbreak 0 kg of contaminated maize. [ProMed 20011007. and then need for a rapid response, directed the 2427]. Field Epidemiology and Laboratory Training Program (KFELTP) to help conduct the The residents also reviewed the steps of an investigation. The KFELTP had just enrolled its outbreak investigation. CDC / Kenya FELTP, 2013: Acute Jaundice in Kenya (122-613) — Participant’s Guide Page 4

Question 3: List the steps of an outbreak investigation.

Question 4: What questions or objectives should the team address with their field investigation?

Question 5: What type(s) of epidemiologic study (or studies) should the team conduct to address those questions and objectives?

Question 6: In this investigation, what are the roles and responsibilities of the residents in the FELTP laboratory track? What are the roles and responsibilities of the residents in the FELTP epidemiology track?

Question 7: Why collect environment samples for laboratory testing? Why collect biologic samples for laboratory testing?

Question 8: Before departing, what preparations and decisions should be made regarding a. the epidemiologic / scientific aspects of the investigation? b. supplies and equipment? c. investigative team composition, role, responsibilities? d. administrative issues? Part II

Working with the DMOHs and others, the Hospital (Makueni District) and Mutomo Mission residents conducted extensive case finding. By Hospital (Kitui District). mid-June, over 300 cases, over 100 deaths. Many of the cases with onsets from mid-May to Table 1 displays the number of cases by week mid-June were hospitalized in just two of symptom onset, from January through June, subdistrict hospitals: Makindu Sub-District 2004.

Table 1. Number of cases of hepatitis by week of onset, Eastern Province, Kenya, 2004

Week Number Week Number beginning cases beginning cases 4 Jan 3 4 Apr 2 11 Jan 3 11 Apr 5 18 Jan 3 18 Apr 13 25 Jan 2 25 Apr 20 1 Feb 1 2 May 23 8 Feb 3 9 May 29 15 Feb 4 16 May 43 22 Feb 0 23 May 24 29 Feb 3 30 May 25 7 Mar 7 6 Jun 36 14 Mar 5 13 Jun 13 21 Mar 5 20 Jun 8 28 Mar 1 27 Jun 13

Question 9: What is an epidemic curve? What is the value of an epidemic curve? Question 10: Using the morbidity data in Table 1, draw an epidemic curve. Table 2. Age, Sex, and Subdistrict of hepatitis patients (n=317), Eastern Province, Kenya, 2004

Number (Percent) Number Case-fatality Characteristic of cases of deaths Rate (%) Age group (years) < 5 68 (21%) 16 24% 5–14 90 (28%) 38 42% ≥ 15 150 (47%) 68 45% Unknown 9 (3%) 3 33% Sex Male 178 (56%) 74 42% Female 139 (44%) 51 37% District Makueni 148 (47%) 78 49% Kitui 101 (32%) 24 24% Other 68 (21%) 28 41%

Total 317(100%) 125 39%

Source: MMWR [3]

Question 11: Summarize the descriptive epidemiology presented in Table 2.

Two recommended actions in investigations of presumed source or vehicle for the agent / toxin, outbreaks attributable to either infectious agents and (2) look for a dose-response relationship. or environmental toxins are to (1) test the

Question 12: Why are both actions recommended?

To document the presence and level of aflatoxin response effect, the team decided to conduct a in maize, the investigators decided to conduct a case-control study. They also planned to test study of aflatoxin concentration in maize. To case-patients and controls for bound aflatoxin in identify risk factors (including exposure to serum and hepatitis B surface antigen. aflatoxin) and to look for a possible dose-

Question 13: What time frame and location(s) would you use for the cases in your case-control study?

Question 14: What are the advantages and disadvantages of including patients who have died in the case group? Before departing for the field, the team developed a case definition.

Question 15: What is a case definition?

Question 16: What case definition would you use for this investigation? Would you include exposure to aflatoxin or aflatoxicosis in your case definition?

Question 17: What sources of controls would you use?

Part III

The investigators used the following case The investigators decided to enroll 40 case- definition: patients, regardless of survival status. They decided to enroll two randomly-selected controls Clinical: acute onset of jaundice of unknown from each case-patient’s village. They did not origin (including no history of cirrhosis or match cases and controls by age or sex, obstructive liver disease) because “…the descriptive epidemiology did not Time: in a patient hospitalized between 18 May find a significant association among sex, case and 9 June 2004 status, and case fatality.” [5] Place/ Person: hospitalized in either Makindu Sub-District Hospital or Mutomo Mission Hospital

Question 18: Do you agree with the investigators’ decision to match on village, but not age or sex? Why or why not?

Question 19: How would you identify the two village-matched controls?

The investigators enrolled 29 living case- patients and 11 patients who had died. They enrolled 80 village-matched controls. Question 20: Which measure of association would you use to analyze the exposure data? [Hint: what type of study is this?]

Table 3. Risk factors for acute unexplained jaundice, case-control study, Eastern Province, Kenya, 2004

Adjusted

Characteristic Cases Controls Odds Ratio (95% CI) Ate homegrown maize kernels Yes * * 3.0 (1.01–8.8) No * * 1.0 (reference) Owned “bad”* homegrown maize kernels Yes * * 5.9 (1.9–18.2) No * * 1.0 (reference) * “bad” = maize with colored flecks, discoloration, unusual odor, or signs of mold Initial dryness of stored maize Wet 15 (54%) 11 (26%) 3.5 (1.2–10.3) Dry 13 (46%) 32 (74%) 1.0 (reference) Storage location House 22 (82%) 23 (54%) 12.0 (1.5–95.7) Granary 5 (18%) 20 (46%) 1.0 (reference) Hepatitis B surface antigen positive Yes 8 (44%) 4 ( 7%) 9.8 (1.5–63.1) No 10 (56%) 50 (93%) 1.0 (reference)

* Actual numbers not provided in report

Source: [5]

Question 21: Describe and interpret these findings.

Part IV

On average, maize samples and serum samples of testing for aflatoxin markers in serum and in were collected 33 days (range 8–112 days) after maize are shown in Table 4. case-patients’ onset of symptoms. The results

Table 4. Laboratory analysis of aflatoxin markers in maize and serum, case-control study of acute unexplained jaundice, Eastern Province, Kenya, 2004

Geometric mean Characteristic Cases Controls P-value Aflatoxin concentration in maize (ppb)* 354.5 44.1 p = 0.04

Aflatoxin B1-lysine adduct concentration In serum (ng/mg of albumin) 1.2 0.15 p < 0.001

* WHO Recommended upper limit for aflatoxin in food = 20 ppb

Source: [5]

Question 22: What is a geometric mean?

Question 21: Interpret the findings in Table 4.

While one investigative team was conducting the (9%) were from Loitokitok or Busia, and 15 (4%) case-control study, another team conducted a were from other Kenya districts. cross-sectional survey to assess the extent of market maize contamination. The survey was Of the 350 samples, 192 (55%) had aflatoxin conducted during a 3-week period in June. The levels greater than the WHO’s recommended survey targeted markets in the four districts in limit (and Kenya’s regulatory limit) of 20 ppb, which 89% of the 319 case-patients resided ― including 121 (35%) with levels > 100 ppb and Makueni, Kitui, Machakos, and Thika. The 24 (7%) with levels > 1,000 ppb. Makueni and markets are a mixture of small, family-owned Kitui districts had the highest proportions of shops and traditional open-air markets where samples with aflatoxin levels > 20 ppb (65% and migrant vendors bring products to sell or trade. 62%, respectively), followed by Machakos (51%) The investigators were able to interview 243 and Thika (35%). Locally grown maize from the vendors and collect 350 maize products from 65 affected area was significantly more likely to markets in 26 of the 31 divisions within the four have aflatoxin levels > 20 ppb than maize from districts. At the time of the survey, most of the other regions of Kenya or imported from other maize was locally grown. So of the 350 product countries (OR = 2.7, 95% CI = 1.1–6.6). samples, 305 (87%) were from local sources, 30

Question 22: What action(s) would you suggest as a result of these findings? Part V – Conclusion

The 2004 outbreak in Kenya, with 317 authorities conducted food inspections and recognized cases and 125 deaths, was one of seized, destroyed, and replaced suspect foods. the largest and most severe outbreaks of acute Surveillance for aflatoxin poisoning was aflatoxicosis documented worldwide. extended to other parts of Kenya.

The case-control study demonstrated an Investigators offered recommendations to association between aflatoxicosis, eating strengthen surveillance, increase food homegrown maize, and storing homegrown inspections to ensure food safety, and provide maize under damp conditions. The maize local education and assistance to ensure that implicated in this outbreak was harvested in maize is harvested correctly, dried completely, February during unseasonable, early rains. To and stored properly. prevent theft of maize left outside the house to dry, maize was stored wet in the house under Unfortunately, Kenya experienced a recurrence conditions conducive to mold growth. of maize-associated aflatoxicosis in the same Furthermore, some of the homegrown maize region in 2005, with at least 14 deaths. Kenya is entered the market distribution system when now considered one of the world’s “hotspots” for local farmers sold a portion of their farm aflatoxin, and a survey conducted as recently as household stores to market vendors. 2010 found widespread evidence of aflatoxin contamination of maize. The government of Kenya provided food replacement in Makueni and Kitui districts. Efforts continue to identify natural, safe, and Residents were advised to avoid consumption of cost-effective solutions to prevent aflatoxin maize or other foods suspected to be moldy or contamination of maize in the future. appearing discolored. In addition, public health

References / Reading 1. Porta M, ed. Dictionary of Epidemiology, 5th ed. New York: Oxford U. Press, 2008. 2. Dicker RC, Coronado F, Koo D, Parish RG. Principles of Epidemiology in Public Health Practice: An Introduction to Applied Epidemiology and Biostatistics. 3rd ed. Atlanta, GA: US Department of Health and Human Services, Centers for Disease Control and Prevention; 2006. Self-Study Course SS1000. 3. CDC. Outbreak of aflatoxicosis poisoning ― Eastern and Central Provinces, Kenya, January–July 2004. MMWR 2004; 53:790–793. 4. Lewis L, Onsongo M, Njapau H, et al. Aflatoxin contamination of commercial maize products during an outbreak of acute aflatoxicosis in Eastern and Central Kenya. Environ Health Perspect 2005; 113: 1763–1767. 5. Azziz-Baumgartner E, Lindblade K, Gieseker K, et al. Case–control study of an acute aflatoxicosis outbreak, Kenya, 2004. Environ Health Perspect 2005; 113: 1779–1783.