Endemicity of Coxiella burnetii infection among people and their livestock in pastoral communities in northern Kenya

Muema, Josphat; Mutono, Nyamai; Wheelhouse, Nick; Njuguna, Joseph; Jost, Christine; Oyugi, Julius; Bukania, Zipporah; Oboge, Harriet; Ogoti, Brian; Makori, Anita; Fernández, María del Pilar; Omulo, Sylvia; Thumbi, Samuel M.

doi:10.1016/j.heliyon.2022.e11133

Cited by 9 publications

(6 citation statements)

References 54 publications

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“…In the present study camels contributed 147 (8.9%) of the 954 ticks that had C. burnetii (Table 4). Whereas a recent study did not find a significant association between high prevalence of Coxiella burnetii in livestock and their owners (46), children have been shown to have a higher predisposition to infection as this pathogen can be transmitted through breast milk (47).…”

Section: Discussionmentioning

confidence: 97%

Detection of pathogenic bacteria in ticks from Isiolo and Kwale counties of Kenya using metagenomics

Kimemia,

Musila,

Lang’at

et al. 2023

Preprint

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Ticks are arachnid ectoparasites which rank second only to mosquitoes in the transmission of human diseases including bacteria responsible for anaplasmosis, ehrlichiosis, spotted fevers, and Lyme disease among other febrile illnesses. Due to paucity of data on bacteria transmitted by ticks in Kenya, this study undertook a bacterial metagenomic-based characterization of ticks collected from Isiolo, a semi-arid pastoralist County in Eastern Kenya, and Kwale, a coastal County with monsoon climate on the southern Kenyan border with Tanzania. A total of 2,918 ticks belonging to 3 genera and 10 species were pooled and screened in this study. Tick identification was confirmed through the sequencing of Cytochrome C Oxidase Subunit 1 (COI) gene. Bacterial 16S rRNA gene PCR amplicons obtained from the above samples were sequenced using the MinION (Oxford Nanopore Technologies) platform. The resulting reads were demultiplexed in Porechop, followed by trimming and filtering in Trimmomatic before clustering using Qiime2-VSearch. A SILVA database pretrained naïve Bayes classifier was used to taxonomically classify the Operational Taxonomic Units (OTUs). The bacteria of clinical interest detected in pooled tick assays were as follows:Rickettsia spp.59.43% of pools,Coxiella burnetii37.88%,Proteus mirabilis5.08%,Cutibacterium acnes6.08% andCorynebacterium ulcerans2.43%. These bacteria are responsible for spotted fevers, query fever (Q-fever), urinary tract infections, skin and soft tissue infections, eye infections and diphtheria-like infections in humans, respectively.P. mirabilis, C. acnesandC. ulceranswere detected only in Isiolo. Additionally, COI sequences allowed for the identification ofRickettsiaandCoxiellaspecies to strain level in some of the pools. Diversity analysis revealed that the tick genera had high levels of Alpha diversity but the differences between the microbiomes of the three tick genera studied were not significant. The detection ofCutibacterium acnes, commonly associated with human skin flora suggests that the ticks may have contact with humans potentially exposing them to bacterial infections. The findings in this study highlight the need for further investigation into the viability of these bacteria and the competency of ticks to transmit them. Clinicians in these high-risk areas also need to be appraised for them to include Rickettsial diseases and Q-fever as part of their differential diagnosis.

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Section: Discussionmentioning

confidence: 97%

Detection of pathogenic bacteria in ticks from Isiolo and Kwale counties of Kenya using metagenomics

Kimemia,

Musila,

Lang’at

et al. 2023

Preprint

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“…The pathogen C. burnetii remains endemic in rural regions of northern Kenya, posing a risk to both human and animal health ( 35 ). Although ticks have been shown to play a role in C. burnetii transmission, their use for non-invasive pathogen surveillance in these ecosystems, shared by livestock, wildlife, and humans, has been largely neglected due to limited diagnostic capability at remote satellite laboratories ( 2 , 16 , 57 ).…”

Section: Discussionmentioning

confidence: 99%

“…Our model estimated that 16% of ticks collected tested positive for C. burnetii DNA, which is consistent with the endemic status of the pathogen in this area. Serological surveys in northern Kenya have reported seroprevalence rates of 10.3% in wild animals ( 30 ), 12.8–83.7% in livestock ( 19 , 20 , 28 , 35 ) and 16.2–24.4% in humans ( 23 , 35 ). It is unknown how accurately these estimates of C. burnetii in ticks translate into true infection prevalence due to the (inherently biased) opportunistic nature of sampling.…”

Section: Discussionmentioning

confidence: 99%

“…Ticks are easy to collect and can be sampled to represent widespread geographical coverage. In known C. burnetii endemic areas, such as northern Kenya ( 35 ), tick species collected from wild animals and their environments have been found to harbor C. burnetii ( 20 , 29 , 36 , 37 ). Furthermore, in these same regions, there was a strong correlation between C. burnetii seropositivity in livestock and their infestation with C. burnetii infected ticks ( 20 , 21 , 26 ).…”

Section: Introductionmentioning

confidence: 99%

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Comparison of test performance of a conventional PCR and two field-friendly tests to detect Coxiella burnetii DNA in ticks using Bayesian latent class analysis

Kamau,

Witte,

Goosen

et al. 2024

Front. Vet. Sci.

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IntroductionCoxiella burnetii (C. burnetii)-infected livestock and wildlife have been epidemiologically linked to human Q fever outbreaks. Despite this growing zoonotic threat, knowledge of coxiellosis in wild animals remains limited, and studies to understand their epidemiologic role are needed. In C. burnetii-endemic areas, ticks have been reported to harbor and spread C. burnetii and may serve as indicators of risk of infection in wild animal habitats. Therefore, the aim of this study was to compare molecular techniques for detecting C. burnetii DNA in ticks.MethodsIn total, 169 ticks from wild animals and cattle in wildlife conservancies in northern Kenya were screened for C. burnetii DNA using a conventional PCR (cPCR) and two field-friendly techniques: Biomeme’s C. burnetii qPCR Go-strips (Biomeme) and a new C. burnetii PCR high-resolution melt (PCR-HRM) analysis assay. Results were evaluated, in the absence of a gold standard test, using Bayesian latent class analysis (BLCA) to characterize the proportion of C. burnetii positive ticks and estimate sensitivity (Se) and specificity (Sp) of the three tests.ResultsThe final BLCA model included main effects and estimated that PCR-HRM had the highest Se (86%; 95% credible interval: 56–99%), followed by the Biomeme (Se = 57%; 95% credible interval: 34–90%), with the estimated Se of the cPCR being the lowest (24%, 95% credible interval: 10–47%). Specificity estimates for all three assays ranged from 94 to 98%. Based on the model, an estimated 16% of ticks had C. burnetii DNA present.DiscussionThese results reflect the endemicity of C. burnetii in northern Kenya and show the promise of the PCR-HRM assay for C. burnetii surveillance in ticks. Further studies using ticks and wild animal samples will enhance understanding of the epidemiological role of ticks in Q fever.

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“…Based on these findings, the authors concluded that camels are a significant reservoir for C. burnetii and can be a primary source of Q fever transmission to humans in Saudi Arabia. In Africa, higher seropositivity rates for Q fever in camels have been reported, with 38.6%, 73.6%, and 75.5% in Kenya, Tunisia, and Algeria, respectively ( 75 – 77 ).…”

Section: Additional Zoonotic Diseases That Camels Could Transmitmentioning

confidence: 99%

Zoonotic diseases transmitted from the camels

Khalafalla

2023

Front. Vet. Sci.

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BackgroundZoonotic diseases, infections transmitted naturally from animals to humans, pose a significant public health challenge worldwide. After MERS-CoV was discovered, interest in camels was raised as potential intermediate hosts for zoonotic viruses. Most published review studies pay little attention to case reports or zoonotic epidemics where there is epidemiological proof of transmission from camels to humans. Accordingly, any pathogen found in camels known to cause zoonotic disease in other animals or humans is reported.MethodsHere, zoonotic diseases linked to camels are reviewed in the literature, focusing on those with epidemiological or molecular evidence of spreading from camels to humans. This review examines the risks posed by camel diseases to human health, emphasizing the need for knowledge and awareness in mitigating these risks.ResultsA search of the literature revealed that eight (36.4%) of the 22 investigations that offered convincing evidence of camel-to-human transmission involved MERS, five (22.7%) Brucellosis, four (18.2%) plague caused by Yersinia pestis, three (13.6%) camelpox, one (4.5%) hepatitis E, and one (4.5%) anthrax. The reporting of these zoonotic diseases has been steadily increasing, with the most recent period, from 2010 to the present, accounting for 59% of the reports. Additionally, camels have been associated with several other zoonotic diseases, including toxoplasmosis, Rift Valley fever, TB, Crimean-Congo hemorrhagic fever, and Q fever, despite having no evidence of a transmission event. Transmission of human zoonotic diseases primarily occurs through camel milk, meat, and direct or indirect contact with camels. The above-mentioned diseases were discussed to determine risks to human health.ConclusionMERS, Brucellosis, plague caused by Y. pestis, camelpox, hepatitis E, and anthrax are the main zoonotic diseases associated with human disease events or outbreaks. Transmission to humans primarily occurs through camel milk, meat, and direct contact with camels. There is a need for comprehensive surveillance, preventive measures, and public health interventions based on a one-health approach to mitigate the risks of zoonotic infections linked to camels.

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Endemicity of Coxiella burnetii infection among people and their livestock in pastoral communities in northern Kenya

Cited by 9 publications

References 54 publications

Detection of pathogenic bacteria in ticks from Isiolo and Kwale counties of Kenya using metagenomics

Detection of pathogenic bacteria in ticks from Isiolo and Kwale counties of Kenya using metagenomics

Comparison of test performance of a conventional PCR and two field-friendly tests to detect Coxiella burnetii DNA in ticks using Bayesian latent class analysis

Zoonotic diseases transmitted from the camels

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