Bao-Ping Zhu

A prolonged, community-wide cholera outbreak associated with drinking water contaminated by sewage in Kasese District, western Uganda

BackgroundIn May 2015, a cholera outbreak that had lasted 3 months and infected over 100 people was reported in Kasese District, Uganda, where multiple cholera outbreaks had occurred previously. We conducted an investigation to identify the mode of transmission to guide control measures.MethodsWe defined a suspected case as onset of acute watery diarrhoea from 1 February 2015 onwards in a Kasese resident. A confirmed case was a suspected case with Vibrio cholerae O1 El Tor, serotype Inaba cultured from a stool sample. We reviewed medical records to find cases. We conducted a case-control study to compare exposures among confirmed case-persons and asymptomatic controls, matched by village and age-group. We conducted environmental assessments. We tested water samples from the most affected area for total coliforms using the Most Probable Number (MPN) method.ResultsWe identified 183 suspected cases including 61 confirmed cases of Vibrio cholerae 01; serotype Inaba, with onset between February and July 2015. 2 case-persons died of cholera. The outbreak occurred in 80 villages and affected all age groups; the highest attack rate occurred in the 5–14 year age group (4.1/10,000). The outbreak started in Bwera Sub-County bordering the Democratic Republic of Congo and spread eastward through sustained community transmission. The first case-persons were involved in cross-border trading. The case-control study, which involved 49 confirmed cases and 201 controls, showed that 94% (46/49) of case-persons compared with 79% (160/201) of control-persons drank water without boiling or treatment (ORM-H=4.8, 95% CI: 1.3–18). Water collected from the two main sources, i.e., public pipes (consumed by 39% of case-persons and 38% of control-persons) or streams (consumed by 29% of case-persons and 24% control-persons) had high coliform counts, a marker of faecal contamination. Environmental assessment revealed evidence of open defecation along the streams. No food items were significantly associated with illness.ConclusionsThis prolonged, community-wide cholera outbreak was associated with drinking water contaminated by faecal matter and cross-border trading. We recommended rigorous disposal of patients’ faeces, chlorination of piped water, and boiling or treatment of drinking water. The outbreak stopped 6 weeks after these recommendations were implemented.

Risk Factors for Podoconiosis: Kamwenge District, Western Uganda, September 2015

AbstractPodoconiosis, a noninfectious elephantiasis, is a disabling neglected tropical disease. In August 2015, an elephantiasis case-cluster was reported in Kamwenge District, western Uganda. We investigated to identify the diseases nature and risk factors. We defined a suspected podoconiosis case as onset in a Kamwenge resident of bilateral asymmetrical lower limb swelling lasting ≥ 1 month, plus ≥ 1 of the following associated symptoms: skin itching, burning sensation, plantar edema, lymph ooze, prominent skin markings, rigid toes, or mossy papillomata. A probable case was a suspected case with negative microfilaria antigen immunochromatographic card test (ruling out filarial elephantiasis). We conducted active case-finding. In a case-control investigation, we tested the hypothesis that the disease was caused by prolonged foot skin exposure to irritant soils, using 40 probable case-persons and 80 asymptomatic village control-persons, individually matched by age and sex. We collected soil samples to characterize irritants. We identified 52 suspected (including 40 probable) cases with onset from 1980 to 2015. Prevalence rates increased with age; annual incidence (by reported onset of disease) was stable over time at 2.9/100,000. We found that 93% (37/40) of cases and 68% (54/80) of controls never wore shoes at work (Mantel-Haenszel odds ratio [ORMH] = 7.7; 95% [confidence interval] CI = 2.0-30); 80% (32/40) of cases and 49% (39/80) of controls never wore shoes at home (ORMH = 5.2; 95% CI = 1.8-15); and 70% (27/39) of cases and 44% (35/79) of controls washed feet at day end (versus immediately after work) (OR = 11; 95% CI = 2.1-56). Soil samples were characterized as rich black-red volcanic clays. In conclusion, this reported elephantiasis is podoconiosis associated with prolonged foot exposure to volcanic soil. We recommended foot hygiene and universal use of protective shoes.

The cost of responding to a waterborne cholera outbreak in a village in Uganda compared to a simple hypothetical intervention, 2016

Introduction : in September 2015, a cholera outbreak occurred in a village in Hoima District, western Uganda. The Ministry of Health assembled a rapid response team, with support by CDC, UNICEF and WHO, to investigate the outbreak, establish the Kaiso Cholera Treatment Center (KCTC), and implement control measures. The team identified 120 cholera cases (with 5 deaths) and determined that drinking contaminated water from the lakeshore caused this outbreak. We sought to determine the cost of investigating and controlling this outbreak, and compare it to a would-be simple preventive measure, constructing deep wells to provide cleaner water. Methods : we collected cost data, including personnel and material costs at KCTC, health facilities, Hoima District Health Office, Uganda Public Health Fellowship Program, UNICEF, CDC, and WHO. We defined direct cost of responding to this outbreak as expenditure on medications, medical equipment and supplies, utilities, and allowances and transport for responders; indirect cost included salary and other compensations for responders. We did not include difficult-to-measure costs such as vehicle depreciation, building maintenance, and loss of productivity to case-persons due to illness and deaths. The cost of constructing deep wells was quoted by a U.S.-based NGO. Results : the total cost incurred in investigating and controlling this outbreak was

Cholera outbreak in a fishing village in Uganda: a case study

71,769, including

Investigating a cholera outbreak in Kaiso Fishing Village, Hoima District, Uganda, October 2015

21,059 in direct cost (

Investigating an outbreak of measles in Kamwenge District, Uganda, July 2015

19,225 for allowances and transportation,

Public health surveillance, outbreak investigations and response to an outbreak of a bleeding illness in Hoima and Buliisa districts, Western Uganda, Sep-Oct 2015

1,774 for medical equipment and supplies, and

Spreading like a wild fire: a tale of three cholera outbreaks, Namayingo District, Uganda, March 2016

60 for utilities), and

Cholera outbreak caused by drinking contaminated water from a lakeshore water-collection site, Kasese District, south-western Uganda, June-July 2015

50,620 in indirect cost (74,484 person-hours of salary and other compensations for responders). Conversely, constructing a deep well to provide cleaner water would cost approximately

Risk factors for hematemesis in Hoima and Buliisa Districts, Western Uganda, September-October 2015

2500. Essentially, the total cost incurred in this outbreak would have been enough to construct 28 (=71769/2500) deep wells; even the direct cost only would have been enough to construct 8 (=21059/2500) deep wells. One such deep well would have prevented this outbreak and averted future waterborne outbreaks. Conclusion : a simple prevention measure such as constructing deep wells for village residents can be substantially cost-effective for preventing waterborne diseases such as cholera. We recommend that the government should proactively implement prevention measures for waterborne outbreaks whenever possible, instead of passively responding to these outbreaks.