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Enhanced Medical Assessment Strategy for Barawan Somali Refugees -- Kenya, 1997

Each year, approximately 100,000 refugees are resettled to the United States. Before resettlement, these refugees undergo medical screening to identify inadmissible conditions (e.g., infectious tuberculosis and human immunodeficiency virus {HIV} infection) among individual refugees. This report describes the implementation and results of an enhanced refugee medical assessment strategy among Barawan Somali refugees in Kenya during July 1997. This strategy employs population-based screening for parasitic infections. The findings indicate that, among these refugees, the prevalences of malaria and intestinal parasites were sufficient to warrant pre-embarkation therapy to improve the health of both individuals and the total refugee population. This therapy also may prevent local transmission of parasitic infections in the resettlement communities in the United States.

In May 1997, resettlement began for approximately 4000 Barawan Somali refugees encamped since 1992 near Mombasa, Kenya. In 1993, detection of substantial malaria parasitemia (15%) among Somali refugees from this region prompted recommendation of antimalarial treatment before resettlement (1). In addition, high prevalences of malaria (30%) and intestinal parasites (60%-80%) had been reported among residents of Kenya living in the coastal region, including Mombasa (S.K. Sharif, M.D., Ministry of Health, Kenya, personal communication, 1997). Because the prevalence of parasitic infections among the Barawan refugees may reflect those of the local community, the International Organization for Migration (IOM) consulted CDC on appropriate pre-embarkation interventions for Barawan refugees. IOM, a nongovernmental organization, medically screens more than half of the refugees resettling to the United States. CDC interim recommendations included mass pre-embarkation therapy with single-dose sulfadoxine-pyrimethamine (SP) for malaria parasitemia and mebendazole (100 mg twice a day for 3 days) for intestinal helminths. During July 1997, CDC conducted a cross-sectional survey of an approximately 10% sample of refugees during the standard medical screening process to 1) determine the prevalences of malaria and intestinal parasites, 2) reevaluate recommended pre-embarkation therapies, 3) assess the effectiveness of the antimalarial regimen, and 4) evaluate the laboratory component of medical screening.

IOM provided information about two groups: refugees examined during February 3-June 23 (travel-approved population, n=3253) and refugees examined during July 7-17 (survey population, n=390). Basic characteristics of the two groups (i.e., age, sex, country of origin, and size of family unit) were similar. Members of the survey population were asked about histories of recent illness and use of medications and other antimalarial preventive measures. A local hospital laboratory screened members of the survey population for malaria by using a qualitative buffy-coat (QBC) test followed by confirmation of all QBC-positives using microscopic examination of Field's-stained blood smears; persons who were positive for malaria were retested 3 and 7 days following completion of antimalarial therapy. Stool specimens were screened at a local hospital for intestinal parasites by direct and formalin ether-concentrated smears. CDC performed quality-control assessments for both the malaria smears and stool samples. Malaria

Of the 390 survey participants, 26 (7%; 95% confidence interval {CI}=4%-10%) were positive for malaria. Of the 26 who were positive, 25 had Plasmodium falciparum parasitemia, and one had P. ovale parasitemia. Because of the severity of the parasitemia and symptoms, the local hospital treated seven of the 26 malaria-positive persons with halofantrine or artemether. Nineteen received a weight-adjusted dose of SP. One patient receiving SP was lost to follow-up. Of the remaining 18 patients receiving SP, 13 were malaria-negative on day 3 of follow-up, and all were malaria-negative by day 7.

Of the surveyed population, recent febrile symptoms were reported by 20% and 37% during initial and follow-up questioning, respectively (Table_1). Use of antimalarial therapy (chloroquine, halofantrine, SP, or quinine) was common among those refugees reporting fever (71% and 93%, respectively). Ten percent of the surveyed refugees reported using any malaria chemoprophylaxis, and most (91%) reported using bed nets (Table_1). Of the 229 refugees reporting the condition of their bed nets, 51 (22%) reported holes or tears in the netting (i.e., poor condition). Use of bed nets in poor condition compared with use of bed nets in good condition was associated with malaria parasitemia (odds ratio=9.2; 95% CI=3.2-27.5).

A total of 37 randomly selected blood smears from refugees reported as parasite-negative by the local hospital were reviewed by CDC and confirmed as negative. However, of the 26 refugees reported as parasite-positive, two cases of P. falciparum parasitemia could not be confirmed by CDC. The smear diagnosed by the local hospital as P. ovale was identified by CDC as P. falciparum. Intestinal Parasites

Stool specimens were obtained from 331 persons; of these, specimens from 129 (39%) were positive for one or more pathogenic intestinal parasites, including Trichuris trichiura (28%), Ascaris lumbricoides (9%), and other pathogens (Table_2). Sex-specific prevalences were similar (41% for females versus 37% for males, chi-square test=0.47, p=0.49). However, age-specific prevalence was higher for persons aged less than 15 years (51%) than for persons aged greater than or equal to 15 years (32%) (chi-square test=11.95, p less than 0.01). CDC reviewed randomly selected negative (n=15) and positive (n=26) stool specimens as determined by the local hospital and found that, for 11 (27%) of these 41 specimens, the local hospital either did not detect or misclassified pathogens that were present in sufficient numbers to detect. The most commonly undetected pathogen was T. trichiura, and the most commonly misclassified pathogen was Entamoeba histolytica.

Reported by: S Gonzaga, MD, V Keane, MPH, B Gushulak, MD, International Organization for Migration, Geneva, Switzerland. H Boyd, Rollins School of Public Health, Emory Univ, Atlanta, Georgia. Div of Parasitic Diseases and Surveillance and Epidemiology Br, Div of Quarantine, National Center for Infectious Diseases, CDC.

Editorial Note

Editorial Note: Although the prevalences of parasitic infections among the Barawan refugees were lower than the prevalences of these infections among persons in the surrounding communities, the prevalences of malaria (7%) and intestinal parasites (39%) among Barawan Somali refugees encamped in Kenya were sufficient to warrant pre-embarkation therapies. The strategy of screening for parasitic infections among a subset of refugees before resettlement provided an opportunity to assess the need for public health interventions for the entire Barawan refugee population. This strategy optimized the efficient distribution of these therapies before the refugees were resettled to the United States. This screening strategy also may be used to determine the need for other pre-embarkation therapies among future refugee populations. However, because the magnitudes of exposures and risks may vary among different groups, the use of specific interventions may differ by refugee group.

CDC oversees refugee health screening in accordance with the Refugee Act of 1980.* The law requires that refugees with medical conditions potentially affecting the public's health be identified and treated; the quality of medical screening and related health services be monitored and assessed; and that health officials in resettlement communities be notified of identified medical conditions. Refugee medical assessments previously focused on identifying inadmissible medical conditions. The enhancement of the medical screening process described in this report emphasizes the expansion of screening to include parasitic diseases with the potential for local transmission in the resettlement community (2,3) and a broadening of the focus from the individual to a population.

As a result of the findings of the enhanced assessment of Barawan Somali refugees, CDC recommended continuation of mass pre-embarkation therapy (day before departure) for malaria infection with SP for all departing refugees who had no contraindication to therapy (i.e., sulfa allergy). This recommendation was based on three considerations. First, the prevalence of parasitemia (7%) may have been underestimated because of the extensive use of presumptive antimalarial therapy for fever. Second, single-dose SP provides adequate cost-effective therapy for P. falciparum. Although the small number of refugees treated with SP (n=19) precluded accurate assessment of the effectiveness of SP, all refugees were malaria-negative by day 7 following SP therapy (n=18, one lost to follow-up). Third, mass pre-embarkation therapy effectively treats symptomatic persons and reduces asymptomatic malaria parasitemia among the entire refugee population, thereby reducing the risk for imported P. falciparum malaria.

Because some Barawan Somali refugees were infected with both helminthic and protozoan pathogens, the interim recommendation for mass pre-embarkation therapy with 3-day mebendazole was changed to single-dose albendazole (400 mg per kg of body weight) for all persons except pregnant women.** This approach was considered preferable because of the high prevalence of mixed intestinal parasites, the low cost of albendazole, and the ease of single-dose therapy before departure (4-6). The optimal choices of agent(s) and duration of therapy for mass treatment of intestinal parasites among refugee populations remain to be determined.

The program of enhanced screening for and management of infectious diseases among this vulnerable refugee population enabled the implementation of population-based interventions before members of this group dispersed to multiple locations in greater than or equal to 20 states. CDC is notifying health officials in the states in which refugees are being resettled of the results of the pre-embarkation medical screening and treatment. CDC also is working with IOM and state refugee health programs to develop a shared database of refugee medical screening results.

References

  1. Slutsker L, Tipple M, Keane V, McCance C, Campbell CC. Malaria in East African refugees resettling to the United States: development of strategies to reduce the risk of imported malaria. J Infect Dis 1995;171:489-93.

  2. CDC. Malaria in Montagnard refugees -- North Carolina, 1992. MMWR 1993;42:180-3.

  3. Gyorkos TW, Frappier-Davignon L, MacLean JD, Viens P. Effect of screening and treatment on imported intestinal parasite infections: results from a randomized, controlled trial. Am J Epidemiol 1989;129:753-61.

  4. Raccurt CP, Lambert MT, Bouloumie J, Ripert C. Evaluation of the treatment of intestinal helminthiases with albendazole in Djohong (North Cameroon). Trop Med Parasitol 1990;41:46-8.

  5. Pungpak S, Singhasivanon V, Bunnag D. Albendazole as a treatment for Giardia infection. Ann Trop Med Parasitol 1996;90:563-5.

  6. Hall A, Nahar Q. Albendazole as a treatment for infections with Giardia duodenalis in children in Bangladesh. Trans R Soc Trop Med Hyg 1993;87:84-6.

* Public Law 96-212.

** Albendazole is currently approved by the Food and Drug Administration for treatment of neurocysticercosis and hydatid disease.



Table_1
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TABLE 1. Number of affirmative responses to initial and follow-up questions about
malaria symptoms among Barawan Somali refugees, 1997
======================================================================================
                                                 Affirmative
                                                  responses
                                           ----------------------
Survey/Characteristic                        No.             (%)  Total respondents
--------------------------------------------------------------------------------------
Initial survey*
Had fever in July                             77            (20)         389
  Received any antimalarial                   54            (71)          76
therapy+
Follow-up survey&
Had fever during May-July                    131            (37)         358
  Received any antimalarial                  122            (93)         131
therapy+
Used chemoprophylaxis                         34            (10)         355
Used bed nets                                325            (91)         355
  Bed nets in poor condition                  51            (22)         229
--------------------------------------------------------------------------------------
* Survey conducted during July 7-17; n=390
+ Chloroquine, sulfadoxine-pyrimethamine, quinine, halofantrine, or artemether.
& Survey conducted July 12 and July 16; n=358
======================================================================================

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Table_2
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TABLE 2. Number and percentage distribution of selected intestinal parasites among Barawan Somali
refugees and comparison of results of stool specimen screening performed by a local hospital
and reviewed by CDC, by parasite, 1997
===================================================================================================
                                                                      Quality review
                                                             -----------------------------------
                                   Survey population*          Local hospital        CDC+
                                  --------------------       ------------------- ---------------
Parasite                           No.             (%)        No.          (%)   No.      (%)
---------------------------------------------------------------------------------------------------
Trichuris trichiura                92             (28)        13          (32)   17      (42)
Ascaris lumbricoides               29             ( 9)         7          (17)    7      (17)
Giardia lamblia                    25             ( 8)         5          (12)    7      (17)
Entamoeba histolytica               7             ( 2)         2          ( 5)    4      (10)
Hookworms                           3             ( 1)         1          ( 2)    0        --
Strongyloides stercoralis           3             ( 1)         1          ( 2)    1      ( 2)
Hymenolepis nana                    3             ( 1)         0            --    0        --
---------------------------------------------------------------------------------------------------
* Stool specimens from survey population tested at a local hospital during July; n=331.
+ Quality review by CDC during October; n=41.
===================================================================================================

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