Surveillance of the Health Status of Bhutanese Refugees -- Nepal, 1992

From February 1991 through July 1992, 67,000 Bhutanese of Nepalese ethnic origin entered the Jhapa and Morang districts of southeastern Nepal (Figure 1) because of ethnic persecution in Bhutan. Six refugee camps were established along the Nepal-India border to accommodate the refugees. In July 1992, to assess the public health needs of these refugees, the Office of the United Nations High Commissioner for Refugees (UNHCR), the Save the Children Fund (SCF), and CDC established a surveillance system to monitor morbidity and mortality. This report describes the surveillance system implemented in these six camps in July 1992 and presents mortality data collected from March through July 1992.

Mortality surveillance was established for six major disease conditions (diarrhea, acute respiratory infections {ARI}, measles, malaria, injuries, maternal deaths, and other/unknown). To encourage timely reporting of deaths, families of the deceased were offered free funeral shrouds and were assured that reporting would not result in a decrease of rations. To uniformly assign a cause of death, a single designated health worker collected mortality data at each camp by interviewing the families. Interviews were structured in a hierarchical fashion starting with the most specific and easily recognized causes of death (i.e., a verbal autopsy). The content and organization of these questions were validated by comparing the cause of death determined from the verbal autopsy with that from more detailed family interviews and reviews of clinical records. Morbidity surveillance was established in the major health center in each camp and was based on clinical case definitions for major causes of morbidity (bloody diarrhea, suspected cholera, other diarrhea, moderate-severe ARI, malaria, measles, suspected hepatitis, suspected encephalitis, injury, or other/unknown).

Mortality data for the period before the institution of systematic surveillance were compiled from camp administrative records. From March 25 through June 30, daily mortality rates for children aged less than 5 years (less than 5MR) averaged over each week were 2.3-8.8 deaths per 10,000 persons per day, a rate 2-8 times greater than the less than 5MR for nonrefugee children in Nepal (1.1 deaths per 10,000 per day) (1). Daily crude mortality rates (CMRs) averaged over each week for the entire camp population were 1.5 deaths per 10,000 per day (range: 1.0-3.0).

Use of verbal autopsies for mortality surveillance enabled determination of cause-specific death rates for the period immediately after surveillance began. Based on verbal autopsies of 89 deaths in persons of all ages during July 3-19, 49 (55%) deaths were due to ARI (0.5 deaths per 10,000 per day) and 25 (28%) were due to diarrhea (0.3 deaths per 10,000 per day). The ARI-specific less than 5MR (1.6 deaths per 10,000 per day) was more than five times greater than the ARI-specific mortality rate for persons aged greater than or equal to 5 years (0.3 deaths per 10,000 per day).

From March 1 through April 30, 549 cases of measles were recorded at camp health centers (attack rate {AR}: 1.7 per 100 population). Following this outbreak, less than 5MRs increased to 4.4-8.8 deaths per 10,000 per day during April 1-May 16. In surveys conducted after a measles vaccination campaign in late May, measles vaccination coverage in children aged 6-59 months was estimated to be 64% (95% confidence interval=60%-69%). However, new cases of measles and measles-related deaths continued to be reported during the first 2 weeks of July 1992.

Multiple antibiotic-resistant Shigella dysentery was an important cause of morbidity. Nearly 12% of patients with diarrhea visiting health centers during July 3-19 had bloody diarrhea. A case of dysentery was defined as fever, more than four stools per day, and blood in the stools confirmed by a health worker. S. flexneri types 1, 2, and 3 were cultured from five of 13 (38%) patients meeting this surveillance case definition. All isolates were resistant to ampicillin, chloramphenicol, and trimethoprim- sulfamethoxazole but sensitive to nalidixic acid. Before use of surveillance definitions, attempts to culture pathogens from patients with a presumed diagnosis of dysentery were unsuccessful, possibly because of misclassification of nonbloody diarrhea as dysentery.

All refugees with illnesses meeting the surveillance case definition for suspected malaria (i.e., fever and shaking chills) were screened using blood smears. From June 15 through July 19, in one camp that had been closed to new arrivals for 2 months, 38 (3.4%) of 1129 refugees with suspected malaria had blood smears slide-positive for Plasmodium falciparum, and 37 (3.3%) had blood smears positive for P. vivax. Most of these persons were probably infected during trips to India; however, some patients may have been infected through endemic transmission.

Systematic mortality and morbidity surveillance has been continued by UNHCR, SCF, and local health authorities. In addition, public health programs have been implemented for diarrheal disease prevention (e.g., improved water and sanitation), screening for malaria infection among new arrivals, and the use of standard guidelines for the appropriate case management of infectious diseases, including dysentery, malaria, and ARI.

Reported by: Program and Technical Support Section, Office of the United Nations High Commissioner for Refugees, Geneva. Save the Children Fund, London. WHO Expanded Programme on Immunization, Kathmandu, Nepal. Arbovirus Diseases Br, Div of Vector-Borne Infectious Diseases, National Center for Infectious Diseases; International Health Program Office, CDC.

Editorial Note

Editorial Note: The findings in this report underscore the types of public health problems that uniquely affect refugees. For example, refugees may lack immunity to some diseases endemic in the host country (2). Specifically, Bhutanese refugees may lack immunity to Japanese encephalitis, which is endemic in Nepal. In addition, a sudden influx of refugees may place local residents of the host country at increased risk for epidemic diseases (3). Although falciparum malaria transmission has been dramatically reduced in southern Nepal since the 1950s, the influx of refugees with malaria poses a potential risk for reestablishing an endemic focus.

CMR is the most specific indicator of health status in refugee populations during the emergency relief phase (i.e., the period when CMRs exceed 1.0 deaths per 10,000 per day {4-6}). Average daily CMRs should be calculated each week to identify mortality trends during the emergency period because the death rate may fluctuate dramatically during this phase (4,5). Reported CMRs are often inaccurate or untimely unless active mortality surveillance is established early in a refugee camp. In the camps in Nepal, mortality rates may have been underestimated because of underreporting of deaths before institution of systematic surveillance (4).

Using simple surveillance case definitions, mortality and morbidity surveillance should be established as early as possible to guide public health planning. Collecting uniform surveillance data in all camps over time provides an important measurement of the efficacy of interventions and allows early recognition of impending epidemics (7). While routine malnutrition prevalence and immunization coverage estimates are essential during the emergency phase, these evaluations are best performed by community-based surveys because of biases involved in clinic-based surveillance.

During the emergency phase in refugee camps, disease and injury surveillance should be simplified and target only the most important potential causes of mortality. Surveillance case definitions should rely on simple clinical diagnostic criteria unless confirmatory laboratory tests are readily available. Surveillance information should be limited to data that will be routinely analyzed to support public health interventions. For example, systematic disease surveillance in these Bhutanese refugee camps led to the rapid recognition of a multiple Shigella outbreak and to the training of local health workers in the case management of ARI and diarrheal diseases. Routine surveillance can be supplemented with special reporting for diseases with epidemic potential during outbreaks (e.g., cholera, meningococcal meningitis, measles, and malaria). During outbreaks, more detailed individual case-report forms can be used to collect information to better guide public health interventions.

To prevent the spread of epidemic diseases to local residents and the refugee population, screening of newly arriving refugees and surveillance for epidemic diseases in refugee camps is essential. Vitamin A administration and measles vaccination should be routinely provided to newly arrived refugees aged less than 5 years to lessen the risk and consequences of epidemic measles. Measles vaccine should be administered in refugee settings even during outbreaks because of the continued influx of potentially susceptible children (8).

References

1. Costello AM de L. Strengthening health care systems to improve infant health in rural Nepal. Trans R Soc Trop Med Hyg 1989;83:19-

3. Suleman M. Malaria in Afghan refugees in Pakistan. Trans R Soc Trop Med Hyg 1988;82:44-7.

4. Fritzsche M, Gottstein B, Wigglesorth M, Eckert J. Serological survey of human cysticercosis in Irianese refugee camps in Papua New Guinea. Acta Trop (Basel) 1990;47:69-77.

5. Toole MJ, Waldman RJ. An analysis of mortality trends among refugee populations in Thailand, Somalia, and Sudan. Bull WHO 1988;6:237-47.

6. Toole MJ, Waldman RJ. Prevention of excess mortality in refugee and displaced populations in developed countries. JAMA 1990;263:3296-302.

7. Dick B, Simmonds SP. Refugee health care: similar but different. Disasters 1983;7:291-303.

8. Moore PS, Toole MJ, Nieberg P, Waldman RJ, Broome CV. Surveillance and control of meningococcal meningitis epidemics in refugee populations. Bull WHO 1990;68:587-96.

9. Toole MJ, Steketee RW, Waldman RJ, Nieburg PI. Measles prevention and control in emergency settings. Bull WHO 1989;67:381-

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