Boelaert, M

Boussery, G

Ejikon, P

Henckaerts, K

van Peteghem, J

English

MSF Field Research

Letters
603 Vol. 7, No. 3 Supplement, June 2001 Emerging Infectious Diseases
Visceral Leishmaniasis (Kala-Azar) Outbreak in
Somali Refugees and Kenyan Shepherds, Kenya
To the Editor: A sharp increase in suspected visceral
leishmaniasis (VL or kala-azar) cases was reported in April
through May 2000 in three Kenyan refugee camps (Ifo,
Dagahaley, and Hagadera). Located around Dadaab town in
Northeastern Province, the three camps house an estimated
125,000 Somali refugees. VL outbreaks have been well
documented in five distinct foci in Kenya (1,2), but until
this outbreak, VL was only sporadically seen in the refugee
camps or the province.
We investigated a possible outbreak in the refugee
sites. Before April 2000, doctors would request a formol-gel
test (FGT) in case of suspected VL and treat an FGT-
positive case with antimonials. Although the FGT is of
uncertain validity, it is still used in district hospitals in
Kenya for lack of alternative diagnostic tests. We consid-
ered a clinician’s request of an FGT as a proxy for “clinical
VL suspicion” and assessed the number of FGTs done from
January 1999 to March 31, 2000. The first suspected VL
patient was traced back to August 1999; this 40-year-old
male Somali refugee had been ill for 8 months and sought
treatment at Dagahaley camp. He responded well to
antimonial treatment. From that date to April 1, 2000, an
FGT was requested for five more patients; results were
positive for two.
Specific surveillance for VL was set up by the refugee
health services in April 2000. Suspected patients or their
caretakers were interviewed. Finger-prick blood was collected
on filter paper and analyzed by direct agglutination test
(DAT) (3). In August 2000, splenic aspirates were performed
on eight patients for direct microscopic examination, and
parasite culture was attempted for three specimens. In vitro
isolation and gp63 polymerase chain reaction-restriction
fragment length polymorphism (PCR-RFLP) molecular
typing was done at the Protozoology Unit of the Prince
Leopold Institute of Tropical Medicine in Antwerp, Belgium.
Serologically or parasitologically confirmed cases were given
stibogluconate (Pentostam), 20 mg/kg/day, for 28 days.
We reviewed surveillance data for the period April 1–
August 31, 2000, and interviewed the health staff. For case
classification, a probable case of VL was illness in a patient
with 1) a fever of >2 weeks’ duration, 2) splenomegaly or
wasting, and 3) positive DAT serology. A confirmed case
had these clinical signs, as well as a positive parasitology
smear or culture. From April 2000 to August 31, 2000, 26
probable (DAT-positive) VL cases were observed and 8
others were confirmed parasitologically. Gp63 PCR-RFLP
molecular typing showed Leishmania donovani in one
specimen. The case-fatality rate was 10 (29.4%) of 34
patients in the group of probable and confirmed VL cases.
Six deaths occurred before treatment could be started, and
one was a complication of the diagnostic procedure (spleen
aspirate).
Thirty-two interviews were completed in the group of
34 probable or confirmed VL patients. Median age was 15
years, and 8 (25) of the 32 were female. Median delay
between onset of symptoms and date of diagnosis was 8
months. Six were Kenyan citizens, five of them shepherds
who were grazing their cattle in the area around Dadaab.
Of the Somali refugees, seven had been living for >2 years
in the refugee camp when their symptoms began. (Five had
been born in the camps.) However, 16 (61.5%) of 26 patients
arrived in the camps after the onset of their symptoms.
Most of them were Ogadeni shepherds, who reportedly
grazed their cattle in the Lower Juba region.
Other evidence points to a serious problem inside
Somalia as well. Médecins sans Frontières reported 48 VL
cases from July 28 to September 21, 2000, in Hudur, Bakol
region. Other nongovernmental organizations reported
cases from several towns in Gedo region. The distribution of
VL in Somalia before the war is poorly documented, but the
disease was known to be endemic in Giohar district, north
of Mogadishu (4). In 1994, Woolhead reported VL in a
woman from Baidoa and warned of potential outbreaks
because of the war (5). Although several of the 34 patients
reported here may have been infected in Somalia, local
transmission in Kenya cannot be excluded, since some of
the refugees denied having left camp and six were Kenyan
citizens.
This outbreak is reason for concern in the context of the
deteriorating nutritional situation in drought-affected
northeastern Kenya. Malnutrition is a known risk factor for
the development of clinical VL in infected persons (6). In
southern Sudan, deaths caused by VL were attributed to
malnutrition in a famine- and war-stricken population (7).
The current nutritional status of the Somali refugees in the
Dadaab camps is precarious. After the 1996 food scarcity
problem (8), food rations for refugees were maintained at
the recommended 2,100 kcal/person/day. In February 2000,
however, the ration was again reduced below the vital
minimum. A cross-sectional random cluster survey on
August 29-31, 2000, showed rising malnutrition levels in
<5-year-old refugee children (Médecins sans Frontières,
unpub. data).
Immediate outbreak control measures have been taken
by refugee camp health authorities, the surveillance system
was strengthened (including initiation of active case-finding
measures), and diagnostic and therapeutic facilities were
upgraded. Six-month peridomestic spraying of the refugee
shelters with lambda-cyhalothrin (ICON) is a routine vector
control measure in the camps. Special attention needs to be
paid, however, to the food security for the refugees in the
light of the current outbreak. Our observations on 16
imported cases also raise concerns about VL transmission
inside Somalia, where access to health care is virtually
nonexistent in many areas and a VL outbreak might go
undetected.
Acknowledgment
We thank the doctors and nurses in the Dadaab refugee health
services for data collection and J.C. Dujardin for species identification.
Günter Boussery,* Marleen Boelaert,†
Joke Van Peteghem,* Philip Ejikon,‡
and Koen Henckaerts*
*Médecins sans Frontières, Brussels, Belgium; †Institute of
Tropical Medicine, Antwerp, Belgium; and ‡Médecins sans
Frontières, Nairobi, Kenya
References
  1. Schaefer KU, Kurtzhals JA, Sherwood JA, Githure JI, Kager PA,
Muller AS. Epidemiology and clinical manifestations of visceral
and cutaneous leishmaniasis in Baringo District, Rift Valley,
Kenya. A literature review. Trop Geogr Med 1994;46:129-33.Letters
604 Emerging Infectious Diseases Vol. 7, No. 3 Supplement, June 2001
  2. World Health Organization. Control of the leishmaniases. Report
of a WHO Expert Committee. World Health Organ Tech Rep Ser
1990;793:1-158.
  3. El Harith A, Kolk AH, Kager PA, Leeuwenburg J, Muigai R,
Kiugu S, et al. A simple and economical direct agglutination test
for serodiagnosis and sero-epidemiological studies of visceral
leishmaniasis. Trans R Soc Trop Med Hyg 1986;80:583-7.
  4. Shiddo SA, Aden Mohamed A, Akuffo HO, Mohamud KA, Herzi AA,
Herzi Mohamed H, et al. Visceral leishmaniasis in Somalia: preva-
lence of markers of infection and disease manifestations in a village
in an endemic area. Trans R Soc Trop Med Hyg 1995;89:361-5.
  5. Woolhead A. A recent case of visceral leishmaniasis in Somalia.
Ann Trop Med Parasitol 1995;89:687-8.
  6. Cerf BJ, Jones TC, Badaro R, Sampaio D, Teixeira R, Johnson
WD Jr. Malnutrition as a risk factor for severe visceral leishma-
niasis. J Infect Dis  1987;156:1030-3.
  7. Seaman J, Mercer AJ, Sondorp E. The epidemic of visceral
leishmaniasis in western Upper Nile, southern Sudan: course
and impact from 1984 to 1994. Int J Epidemiol 1996;25:862-871.
  8. Boelaert M, Englebert M, Hanquet G, Van Damme W, Van der
Stuyft P. Refugee relief rations. Lancet 1997;349:1775.
Doxycycline and Eradication of
Microfilaremia in Patients with Loiasis
To the Editor: Wolbachia are intracellular symbionts found
in 20% of insects and in several nematodes, including filarial
worms. Because tetracycline eradicates Wolbachia in nema-
todes, this drug has been proposed for chemotherapy in
filariasis (1). We report two patients with loiasis in whom
no Wolbachial DNA was detected in microfilariae by poly-
merase chain reaction (PCR), and for whom 6 weeks of
doxycycline failed to eradicate the microfilaremia. We conclude
that doxycycline may not be an efficient therapy for loiasis.
Filariae are responsible for 150 million infections
worldwide, some of them devastating diseases such as
elephantiasis (caused by Bancroftian and Brugian filaria-
sis) and blindness (caused by onchocerciasis). There is no
satisfactory treatment for filariasis: although diethycarbam-
azine citrate has been used for 50 years to treat the disease,
this drug is not efficient in most adults (2). Ivermectin has
been reported to be efficient in treating microfilaremia and
possibly for viability and fertility of adult Oncocerca volvulus
worms if therapy is prolonged for 2 to 3 years (2). However,
the microfilaricidal effect of ivermectin on Wuchereria,
Brugia, and Loa loa is similar to diethycarbamazine: ultra-
sonography shows that it has no effect on adult Bancroftian
worms, and microfilariae often reappear after a few months (2).
Intracellular bacteria have been observed in the lateral
cords of adult female worms as well as in microfilariae of
W. bancrofti, and these bacteria have recently been identi-
fied as belonging to the Wolbachia genogroup (3). Wolbachia
have been detected by PCR in Brugian and Bancroftian
filariae, dirofilariae, and most species of Oncocerca includ-
ing O. volvulus, but have never been detected in L. loa
worms (4). Wolbachia are causative agents of a variety of
modifications in host development and reproduction,
including cytoplasmic incompatibility and parthenogenesis.
Consequently, it has been proposed that antibiotic eradica-
tion of Wolbachia from infected filarial worms would reduce
microfilaremia. This has been demonstrated in an animal
model with Litomosoides sigmodontis and recently
confirmed in patients infected with O. volvulus (1-5). In
experimental L. sigmodontis infection, after 41 days of
therapy, microfilaremia in tetracycline-treated animals was
one-tenth that in normally infected animals (5).
We report the failure of tetracycline to reduce microfila-
remia in two patients with L. loa filariasis. Patient no. 1
was a 58-year-old man who worked in Gabon for many
years and had cutaneous larva migrans. L. loa microfilare-
mia was detected (4x103/mL). Patient no. 2, a 15-year-old
boy living in Cameroon, was diagnosed with Calabar
swelling with L. loa microfilaremia (1x103/mL). After giving
informed consent, both patients were treated with doxycy-
cline 200 mg daily for 6 weeks as previously described in
O. volvulus-infected patients (1). We observed patients for
microfilaremia every week for 6 weeks and then every 2
weeks for 2 months. The presence of adult worms was
detected by physical examinations.
 Microfilaremia was detected in both patients at the
completion of treatment and at day 120 of follow-up. In
patient no. 1, the frequency of migrating adult worms
seemed to diminish during therapy, but they never disap-
peared. For Wolbachia detection in worms, blood samples
were collected both in Dupont-Isolator and EDTA-contain-
ing tubes. After centrifugation at 5000 x g for 30 min, the
worm-enriched pellet was resuspended in 1 mL of sterile
deionized water for erythrocyte lysis. DNA was extracted
from the suspension by using the QIAmp-blood kit (Qiagen,
Hilden, Germany) following manufacturer’s recommenda-
tions. W. pipientis DNA was used as a positive control.
Control of DNA extraction was performed by amplifying
microfilarial DNA using the nematode-specific 18S r DNA-
derived primers 18SF (5'-GAT-ACC-GCC-CTA-GTT-CTG-
ACC-3') and 18SR (5'-ACC-AAC-TAA-GAA-CGG-CCA-TG-
3'). Wolbachia detection was attempted with the FD1 (5'-
AGA-GTT-TGA-TCC-TGG-CTC-AG-3') and Rp2 (5'-ACG-
GCT-ACC-TTG-TTA-CGA-CTT-3') eubacterial primers, with
the Ehrlichia genus-specific 16S rDNA primers EHR16SD
(5'-GGT-ACC-YAC-AGA-AGA-AGT-CC-3') and EHR16SR
(5'- TAG-CAC-TCA-TCG-TTT-ACA-GC-3'), and with primers
specific for the 16S r DNA of B. malayi endosymbiont, Bsymbf
(5'-ACG-AGT-TAT-AGT-ATA-ACT-3'), and Bsymbr (5'-CCT-
TCG-AAT-AGG-AAT-AAT-3') (3-6). PCR reactions were
performed on PTC-200 thermocycler (MJ-Research, USA) by
using 45 cycles of denaturation at 94°C for 30 sec, hybrid-
ization for 45 sec, and elongation at 72°C for 1 min. Hybrid-
ization temperatures were 55°C for FD1/Rp2, 53°C for
EHR16SD/ EHR16SR, 42°C for Bsymbf/Bsymbr, and 57°C for
18SF/18SR. Experiments were repeated three times.
We detected Wolbachia in the positive control and 18s
rRNA of the nematode in the sample, but no signal compati-
ble with Wolbachial DNA was obtained with the sets of
primers used. In fact, four species of filariae (Dipetalonema
setariosum, Acanthocheilonema vitae, O. flexuosa, and
L. loa) tested for intracellular bacteria by electron microsco-
py, immunohistochemistry, or PCR had no bacteria (4). The
absence of Wolbachia in L. loa microfilariae may explain
the failure of tetracycline therapy in our patients.
More work is needed to determine the prevalence of
Wolbachia in filariae, their impact on fertility in each
species, and the use of antibacterial agents for eradicating
these pathogens.
Acknowledgment
We thank MJ Taylor for providing W. pipientis DNA for controls.

A simple and economical direct agglutination test for serodiagnosis and sero-epidemiological studies of visceral leishmaniasis. Trans R Soc Trop Med Hyg

Epidemiology and clinical manifestations of visceral and cutaneous leishmaniasis in Baringo District, Rift Valley, Kenya. A literature review. Trop Geogr Med 1994;46:129-33.

Malnutrition as a risk factor for severe visceral leishmaniasis.

The epidemic of visceral leishmaniasis in western Upper Nile, southern Sudan: course and impact from

Visceral leishmaniasis in Somalia: prevalence of markers of infection and disease manifestations in a village in an endemic area. Trans R Soc Trop Med Hyg 1995;89:361-5. 5. Woolhead A. A recent case of visceral leishmaniasis in Somalia.

Visceral leishmaniasis (kala-azar) outbreak in Somali refugees and Kenyan shepherds, Kenya.

Günter Boussery

Marleen Boelaert

Joke Van Peteghem

Philip Ejikon

Koen Henckaerts

Directory of Open Access Journals

Emerging Infectious Diseases

Visceral Leishmaniasis (Kala-Azar) Outbreak in Somali Refugees and Kenyan Shepherds, Kenya

Crossref

Visceral leishmaniasis (kala-azar) outbreak in Somali refugees and Kenyan shepherds, Kenya.

Abstract

Similar works

Full text

Available Versions

MSF Field Research

Directory of Open Access Journals

Crossref