Monthly fluctuation of Ixodid tick infestation on indigenous goats in Botswana

Anaplasma is a genus of gram-negative, intracellular bacteria infecting different blood cells in animals. A. ovis infects erythrocytes of sheep and goats, inducing clinical signs that include haemolytic anaemia, icterus and loss of production. Aim of this study was to evaluate the prevalence of Anaplasma spp. in goats in smallholder flocks around Gaborone, Botswana. Whole blood and serum samples were collected from 100 goats coming from 10 smallholder goat flocks from three villages around Gaborone, Botswana. Body condition and FAMACHA© scores were estimated. Blood was used for packed cell volume (PCV), blood smears, PCR, including species-specific PCR assays for A. marginale and A. ovis, and serum samples were analysed by Anaplasma spp. cELISA. Each farmer was interviewed about management, health and treatment of the goats. Microscopic examination of Giemsa-stained blood smears showed inclusion bodies in 53% of the samples. A seroprevalence of 88% was found on cELISA and 76% of the goats were positive by PCR using general primers for Anaplasma spp. All PCR positive goats were infected with A. ovis and no goats were positive for A. marginale. Positive animals were found in all areas and in all flocks. There was no correlation between infection and clinical signs. In Botswana, A. ovis in goats does not seem to pose a significant problem even though the pathogen is endemic in the goat population, or perhaps, because of being endemic, herd immunity leads to less severe clinical signs.

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“…Rhipicephalus evertsi is the tick species considered to transmit Anaplasma spp. to goats in the area of this study (Mushi et al 1996).…”

Section: Introductionmentioning

confidence: 79%

“…The most important genera of ticks that transmit Anaplasma spp. are Ixodes, Dermacentor, Rhipicephalus and Amblyomma (Rymaszewska and Grenda 2008), of which Rhipicephalus and Amblyomma have been found on goats in Botswana (Mushi et al 1996). Rhipicephalus evertsi is the tick species considered to transmit Anaplasma spp.…”

Section: Introductionmentioning

confidence: 99%

Anaplasma ovis infection in goat flocks around Gaborone, Botswana

et al. 2019

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“…Babesia ovis has been reported to be transmitted by Rhipicephalus turanicus and Hyalomma anatolicum Yeruham et al (1992) and Friedhoff, (1997). Climatic conditions particularly temperature, rainfall, relative humidity and the length of the rainy season have been demonstrated as the important factors affecting the life cycle and abundance of ticks, (Mushi et al, 1996 ;Yeruham et al, 1996;23 Yakhchali and Hosseine, 2006).…”

Section: Discussionmentioning

confidence: 99%

Seroprevalence of Babesia ovis in small ruminants in Siwa Oasis, Egypt

Hosein

Ahmed

Ibrahim

et al. 2007

Journal of Veterinary Medical Research

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A total of 240 blood samples were collected from 108 sheep and 132 goats for preparation of blood smears and for separation of serum samples and tested against B. ovis by using IFAT. B. ovis was detected in 55 (50.92%) and 59 (44.69%) blood smears examined in sheep and goats, respectively. The overall prevalence of B. ovis infection was 71.3% in sheep and 68.2% in goat using IFAT. The seasonal prevalence of B.ovis peaked in both spring and summer as revealed by blood smear examination and IFAT. A total of 143 ticks were collected from 62 sheep and 81 goats during the study. The ticks examined were Rhipicephalus turanicus (75.52%) and Hyalomma anatolicum (24.48%).

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“…Previous studies have found that hard-bodied ticks in most systems prefer higher humidity and intermediate temperatures and are at their lowest numbers on hosts in very hot, dry seasons [55]. As ticks were actually less prevalent on ENP zebras during what should have been their preferred season, this lends more evidence that immunomodulatory conditions influenced tick infestation of hosts.…”

Section: Seasonal Immune Resource Allocationmentioning

confidence: 79%

Gastrointestinal helminths may affect host susceptibility to anthrax through seasonal immune trade-offs

et al. 2014

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Background: Most vertebrates experience coinfections, and many pathogen-pathogen interactions occur indirectly through the host immune system. These interactions are particularly strong in mixed micro-macroparasite infections because of immunomodulatory effects of helminth parasites. While these trade-offs have been examined extensively in laboratory animals, few studies have examined them in natural systems. Additionally, many wildlife pathogens fluctuate seasonally, at least partly due to seasonal host immune changes. We therefore examined seasonality of immune resource allocation, pathogen abundance and exposure, and interactions between infections and immunity in plains zebra (Equus quagga) in Etosha National Park (ENP), Namibia, a system with strongly seasonal patterns of gastrointestinal (GI) helminth infection intensity and concurrent anthrax outbreaks. Both pathogens are environmentally transmitted, and helminth seasonality is driven by environmental pressures on free living life stages. The reasons behind anthrax seasonality are currently not understood, though anthrax is less likely directly driven by environmental factors. Results: We measured a complex, interacting set of variables and found evidence that GI helminth infection intensities, eosinophil counts, IgE and IgGb antibody titers, and possibly IL-4 cytokine signaling were increased in wetter seasons, and that ectoparasite infestations and possibly IFN-γ cytokine signaling were increased in drier seasons. Monocyte counts and anti-anthrax antibody titers were negatively associated with wet season eosinophilia, and monocytes were negatively correlated with IgGb and IgE titers. Taken together, this supports the hypothesis that ENP wet seasons are characterized by immune resource allocation toward Th-2 type responses, while Th1-type immunity may prevail in drier seasons, and that hosts may experience Th1-Th2 trade-offs. We found evidence that this Th2-type resource allocation is likely driven by GI parasite infections, and that these trade-offs may render hosts less capable of concurrently mounting effective Th1-type immune responses against anthrax. Conclusions: This study is one of the first to examine laboratory-demonstrated Th1-Th2 trade-offs in a natural system. It provides evidence that seasonally bound pathogens may affect, through immunology, transmission dynamics of pathogens that might otherwise not be seasonally distributed. It suggests that, by manipulating the internal host ecosystem, GI parasites may influence the external ecosystem by affecting the dynamics of another environmentally transmitted pathogen.

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Monthly fluctuation of Ixodid tick infestation on indigenous goats in Botswana

Cited by 10 publications

References 3 publications

Anaplasma ovis infection in goat flocks around Gaborone, Botswana

Anaplasma ovis infection in goat flocks around Gaborone, Botswana

Seroprevalence of Babesia ovis in small ruminants in Siwa Oasis, Egypt

Gastrointestinal helminths may affect host susceptibility to anthrax through seasonal immune trade-offs

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