Prevalence and risk factors associated with Ehrlichia infections in smallholder dairy cattle in Nairobi City County, Kenya

Abstract

Background and Aim: Ehrlichiosis caused by Ehrlichia ruminantium is a tick-borne disease of great economic importance in cattle production worldwide. Despite its economic impact, limited knowledge is available on its epidemiology in Africa, including Kenya. Suspected cases of E. ruminantium infections have been reported in the recent past to the University of Nairobi's Veterinary Hospital, prompting the need to investigate their possible re-emergence. Therefore, this study was aimed at determining the prevalence of E. ruminantium among smallholder dairy cattle in Nairobi City County and to assess potential risk factors. This knowledge may guide the development of appropriate control strategies of ehrlichiosis, subsequently reducing associated losses. Materials and Methods: A total of 107 smallholder dairy farms from Nairobi City County were recruited for the study. Blood samples were collected from 314 apparently healthy dairy cattle, and Giemsa-stained blood smears were screened under the microscope for Ehrlichia species. A commercial antigen enzyme-linked immunosorbent assay (ELISA) kit was then used to confirm the presence of the infections in serum samples. A pre-tested questionnaire was used to collect data on management practices that may be potential risk factors. A univariate and mixed-effects logistic regression was then used to determine significant risk factors. Results: On microscopy, 79.3% (249/314) of the sampled animals had Ehrlichia-like inclusion bodies in white blood cells, though only 18.6% (95% confidence interval [CI] 14.2-23.0) of these were confirmed to be E. ruminantium on ELISA. A farm-level prevalence of 35.5% (95% CI 27.0-45.3) was reported. Female-headed households (p=0.013), farms in Langata region (p=0.027), cleaning of cowsheds fortnightly (p=0.019), and roofing of cowshed (p=0.022) were factors significantly associated with E. ruminantium infections. Conclusion: There is a relatively high prevalence of E. ruminantium infections in apparently healthy cattle in smallholder dairy farms in this area, warranting control measures. It is critical to improve animal welfare-related factors, such as cowshed cleaning and roofing, as well as the strategic location of farms, especially, since reservoirs may reduce infection levels in the farms, in relation to wildlife. However, since Ehrlichia-like inclusion bodies other than those of E. ruminantium were observed in this study, there is a need to investigate further these factors and the possibility of other Ehrlichia species infecting cattle in the study area.

Molecular prevalence of emerging Anaplasma and Ehrlichia pathogens in apparently healthy dairy cattle in peri-urban Nairobi, Kenya

“…The study area and design have been described in detail previously [23]. This was a cross-sectional study undertaken between January and May 2017.…”

“…Previously, there had been clinical cases reported to the University of Nairobi Veterinary Hospital, Kenya presenting with unspecific clinical signs such as unthriftness and loss of body conditions. On screening of cattle from the areas where the clinical cases had originated, E. ruminantium was identified by antigen detection using Enzyme-linked Immunosorbent Assay (ELISA) [23]. Additionally, microscopic examination of blood from these cattle revealed that some of them had Ehrlichia-like inclusion bodies in the white blood cells suggesting infections with other unknown potentially pathogenic haemoparasites [23].…”

“…On screening of cattle from the areas where the clinical cases had originated, E. ruminantium was identified by antigen detection using Enzyme-linked Immunosorbent Assay (ELISA) [ 23 ]. Additionally, microscopic examination of blood from these cattle revealed that some of them had Ehrlichia -like inclusion bodies in the white blood cells suggesting infections with other unknown potentially pathogenic haemoparasites [ 23 ]. Hence, there was need to identify and characterize those Ehrlichia -like inclusion bodies observed in these animals.…”

Identification of Amblyomma javanense and detection of tick-borne Ehrlichia spp. in confiscated Malayan Pangolins

“…E. ruminantium , initially named as Rickettsia ruminantium , was the first species of Ehrlichia to be discovered. E. ruminantium infected ruminants mainly in African areas such as Kenya and Uganda ( Allsopp, 2010 ; Peter et al, 2019 ; Tumwebaze et al, 2020 ), and in other areas like Northwest China ( Guo et al, 2018 ) and Oman ( El-Neweshy et al, 2019 ). However, E. ruminantium were also reported in free-living jaguars in Brazil ( Widmer et al, 2011 ).…”

Molecular detection of Anaplasma phagocytophilum DNA in Olive Baboons and Vervet monkeys in Kenya

“…Recent reports on animal anaplasmosis are available from France, Massachusetts, Brazil, Zambia Ethiopia and Kenya in both domestic and wild animals [17][18][19][20][21][22]. While Anaplasma in NHPs has been reported in some countries, its importance in NHPs in Kenya is not yet known which has therefore led us to investigate the occurrence of this bacteria in NHPs in Laikipia, Kenya.…”