Diversity and temporal fluctuations in abundance of rodents, shrews and their flea- ectoparasites in an extensive agricultural landscape of Mgeta division, Morogoro region, Tanzania
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Date
2024-05
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Sokoine University of Agriculture
Abstract
Rodents and shrews play an important role in a variety of
ecosystems including crop farming and the keeping of food animals.
Increasing cultivation of crops and livestock keeping in Mgeta
division, along the western slopes of Uluguru Mountain, is
threatening the survival of rodents and shrews, and consequently,
changes in the likelihood of these animals in their disease
transmission patterns, which involves also their ectoparasites,
particularly fleas, due to changes in their abundance and distribution
in the ecosystem. This study was conducted from December 2021
to May 2022, and intended to investigate the diversity and temporal
fluctuations in abundance of rodents, shrews and their flea-
ectoparasites in Mgeta, an area with extensive agriculture in south-
east Tanzania. Three habitats (forest, fallow and cultivated lands),
each, were selected and defined as low (1,100 - 1,500 m a.s.l) and
high (1,600 - 1,900 m a.s.l) elevations and subsequently sampled for
rodents, shrews and their flea-ectoparasites. Removal trapping with
baited live Sherman®, Harvahart® and locally made traps was carried
out. A total of 192 rodents and 15 shrews were captured, and 199
fleas were collected. Identification of the rodents, shrews and fleas
was done up to their species levels. Captured rodents included:
Rattus rattus (1.45%), Mastomys natalensis (9.66%), Beamys hindei
(1.45%), Lophuromys flavopunctatus (21.74%), Lophuromys kilonzoi
(2.42%), Praomys delectorum (40.58%), Grammomys ibeanus
(8.7%), Graphiurus murinus (1.45%), Mus minutoides (3.38%), Mus
musculus (1.45%) and Dasmys spp (0.48%), whereas, the shrew
species included: Crocidura olivieri (3.86%) and Crocidura hirta
(3.38%). A Total number of 95 (45.89%) rodents and 6 (2.8%)
shrews were infested by Dinopsyllus lypusus, Nosopsyllus fasciatus
or Ctenopthalmus calceatus. The mean abundance of fleas
presented a significant variation among the host species (F (12, 194) =
11.82, P < 0.001), habitats (F (2, 204) = 9.935, P < 0.001) and along
the elevation gradient (F (1, 205) = 10.15, P = 0.02). Similarly, the
prevalence varied significantly between the hosts (F (12, 194) = 22.44, P < 0.001) and habitats (F (2, 204) = 4.837, P = 0.009) but not with
elevation (F (1, 205) = 0.291, P = 0.59). The mean intensity of flea
infestation, on the other hand, varied significantly among the hosts
(F (12, 194) = 9.257, P < 0.001) and along the elevation gradient (F (1,
205) = 47.91, P < 0.001), but not habitats (F (2, 204) = 0.75, P = 0.474).
Furthermore, while rainfall intensity was strongly associated with
mean abundance of fleas (r = 0.054, P < 0.05), neither temperature,
elevation, nor humidity were correlated with either mean intensity or
prevalence of fleas on the hosts. However, rainfall, temperature, and
relative humidity had a significant effect on rodent and shrew
abundance (P< 0.05). Given the discovery of D. lypusus, which is a
well-known vector of the plague pathogen, Yersinia pestis, and a
common ectoparasite of M. natalensis and R. rattus. Effective
conservation strategies to preserve the remainder forest patches
and community awareness programs regarding the existence of
potential plague vectors and mitigation measures in the study area
as well as avoidance mechanism should be implemented to ensure
the health of the entire ecosystem.
Description
MSc. Public Health Pest Management
Keywords
Rodents, Shrews, Their Flea- Ectoparasites, Extensive Agricultural Landscape, Mgeta Division, Morogoro Region, Tanzania