| dc.description.abstract | Identification of animal reservoirs of leishmaniasis
is an absolute pre-requisite to understanding the
epidemiology of the disease. A 16-month search for
animal reservoirs of leishmaniasis began in Marigat
Location of Baringo District in May 1986 and in Masinga
Location of Machakos District in December 1987.
Epidemics were reported in these areas during the 1950s
and 1970s and current endemicity of the disease suggest
that animal reservoirs maintain the infection.
Examination for leishmanial parasites was done, using
culture and smear techniques. From Marigat, a total of
1,128 rodents belonging to 7 genera and 11 carnivores
belonging to 3 genera were examined; and from Masinga,
633 rodents belonging to 10 genera and 95 carnivores
belonging to 5 genera were examined. From Marigat, 3
(0.5%) Arvicanthis niloticus, 36 (12.5%) Tatera robusta
and 2 (0.8%) Mastomys natalensis were positive for
leishmanial parasites. From Masinga, no leishmania
infection was detected but 67 (60.4%) Acomys
subspinosus, 12 (8.4%) Mastomys natalensis, 2 (4.0%)
Lemniscomys striatus, 2 (33.3%) Herpestes sanguineus, 1
(100%) Helogale parvula and 1 (1.2%) Canis familiaris
were found positive with trypanosome flagellates.
Forty-two isolates from sandflies, 34 from humans and
13 from lizards all obtained from the study sites were
included for comparlson with isolates from wild animals.
All isolates were characterized by isoenzyme analysis
using nine enzymes. The enzymes examined were: malate
dehydrogenase (MDH), phosphoglucomutase (PGM), glucose
phosphate isomerase (GPl), isocitrate dehydrogenase
(leD), nucleoside hydrolase (NH), glucose 6-phosphate
dehydrogenase (G6PD), malic enzyme (ME),
6-phosphogluconate dehydrogenase (6PGD) and mannose
phosphate isomerase (MPl). The isolates were compared
with five Old World Leishmania reference strains and
five well characterized rodent trypanosomes of the
subgenus Herpetosoma. All the isolates from rodents In
Marigat (except one from a Mastomys) were identified as
Leishmania major. Of the 34 isolates from humans, 31
were identified as L. donovani and three as ~. major.
Thirty-four isolates from Sergentomyia spp. and 13 from
lizards were all identified as L. adleri. Five P.
duboscqi and 3 P. martini isolates were identified as L.
major and donovani respectively.
All the isolates from animals from Masinga and one
from a Mastomys from Marigat differed from the
Leishmania reference strains. They were, however,
morphologically similar to rodent trypanosomes. The
enzyme profiles of the three mongoose isolates were
identical to each other but different from rodent and
dog isolates.
The results of the studies in Marigat suggest that
rodents are the reserVOlrs of cutaneous leishmaniasis 1n
Baringo District, with Tatera robusta serving as the
main reservolr. Leishmania major was not isolated
from animals in Masinga.
The prevalence of mammalian trypanosome flagellates
was very high in Acomys (60.4%) collected in Masinga but
in Marigat, only one Mastomys (0.004%) was found
infected with trypanosome flagellates.
Mastomys and Acomys were found to be susceptible to
experimental infection with L. donovani while dogs, cats
and goats were found to be refractory to the infection.
Although rodents were susceptible, none were found
naturally infected with 1. donovani. The results in
this study argue against the notion that wild mammals
and/or dogs serve as reservoirs of visceral
leishmaniasis and support the suspicion that man is
probably the only reservoir of infection in Kenya. | en |
