http://repository.anu.ac.ke/handle/123456789/685 2026-09-13T05:38:01Z 2026-09-13T05:38:01Z Mwamuye, Micky M http://repository.anu.ac.ke/handle/123456789/1217 2026-09-10T08:48:40Z 2017-05-01T00:00:00Z

Molecular Detection of Tick-Borne Pathogen Diversities in Ticks from Livestock and Reptiles along the Shores and Adjacent Islands of Lake Victoria and Lake Baringo, Kenya Mwamuye, Micky M Although diverse tick-borne pathogens (TBPs) are endemic to East Africa, with recognized impact on human and livestock health, their diversity and specific interactions with tick and vertebrate host species remain poorly understood in the region. In particular, the role of reptiles in TBP epidemiology remains unknown, despite having been implicated with TBPs of livestock among exported tortoises and lizards. Understanding TBP ecologies, and the potential role of common reptiles, is critical for the development of targeted transmission control strategies for these neglected tropical disease agents. During the wet months (April–May; October–December) of 2012–2013, we surveyed TBP diversity among 4,126 ticks parasitizing livestock and reptiles at homesteads along the shores and islands of Lake Baringo and Lake Victoria in Kenya, regions endemic to diverse neglected tick-borne diseases. After morphological identification of 13 distinct Rhipicephalus, Amblyomma, and Hyalomma tick species, ticks were pooled (≤8 individuals) by species, host, sampling site, and collection date into 585 tick pools. By supplementing previously established molecular assays for TBP detection with high-resolution melting analysis of PCR products before sequencing, we identified high frequencies of potential disease agents of ehrlichiosis (12.48% Ehrlichia ruminantium, 9.06% Ehrlichia canis), anaplasmosis (6.32% Anaplasma ovis, 14.36% Anaplasma platys, and 3.08% Anaplasma bovis,), and rickettsiosis (6.15% Rickettsia africae, 2.22% Rickettsia aeschlimannii, 4.27% Rickettsia rhipicephali, and 4.95% Rickettsia spp.), as well as Paracoccus sp. and apicomplexan hemoparasites (0.51% Theileria sp., 2.56% Hepatozoon fitzsimonsi, and 1.37% Babesia caballi) among tick pools. Notably, we identified E. ruminantium in both Amblyomma and Rhipicephalus pools of ticks sampled from livestock in both study areas as well as in Amblyomma falsomarmoreum (66.7%) and Amblyomma nuttalli (100%) sampled from tortoises and Amblyomma sparsum (63.6%) sampled in both cattle and tortoises at Lake Baringo. Similarly, we identified E. canis in rhipicephaline ticks sampled from livestock and dogs in both regions and Amblyomma latum (75%) sampled from monitor lizards at Lake Victoria. These novel tick–host–pathogen interactions have implications on the risk of disease transmission to humans and domestic animals and highlight the complexity of TBP ecologies, which may include reptiles as reservoir species, in sub-Saharan Africa.

2017-05-01T00:00:00Z Mwamuye, Micky M. http://repository.anu.ac.ke/handle/123456789/1216 2026-09-10T08:34:59Z 2017-02-01T00:00:00Z

Novel Rickettsia and emergent tick-borne pathogens: A molecular survey of ticks and tick-borne pathogens in Shimba Hills National Reserve, Kenya Mwamuye, Micky M. Ticks are important vectors of emerging and re-emerging zoonoses, the majority of which originate from wildlife. In recent times, this has become a global public health concern that necessitates surveillance of both known and unknown tick-borne pathogens likely to be future disease threats, as well as their tick vectors. We carried out a survey of the diversity of ticks and tick-borne pathogens in Kenya’s Shimba Hills National Reserve (SHNR), an area with intensified human-livestock-wildlife interactions, where we collected 4297 questing ticks (209 adult ticks, 586 nymphs and 3502 larvae). We identified four tick species of two genera (Amblyomma eburneum, Amblyomma tholloni, Rhipicephalus maculatus and a novel Rhipicephalus sp.) based on both morphological characteristics and molecular analysis of 16S rRNA, internal transcribed spacer 2 (ITS 2) and cytochrome oxidase subunit 1 (CO1) genes. We pooled the ticks (3–8 adults, 8–15 nymphs or 30 larvae) depending on species and life-cycle stages, and screened for bacterial, arboviral and protozoal pathogens using PCR with high-resolution melting analysis and sequencing of unique melt profiles. We report the first molecular detection of Anaplasma phagocytophilum, a novel Rickettsia-like and Ehrlichia-like species, in Rh. maculatus ticks. We also detected Ehrlichia chaffeensis, Coxiella sp., Rickettsia africae and Theileria velifera in Am. eburneum ticks for the first time. Our findings demonstrate previously unidentified tick-pathogen relationships and a unique tick diversity in the SHNR that may contribute to livestock, and possibly human, morbidity in the region. This study highlights the importance of routine surveillance in similar areas to elucidate disease transmission dynamics, as a critical component to inform the development of better tick-borne disease diagnosis, prevention and control measures. Abbreviations SHNR, Shimba Hills National Reserve; HRM, high-resolution melting; EID, emerging infectious disease; TBD, tick-borne disease; CO1, cytochrome oxidase subunit 1; ITS 2, internal transcribed spacer 2; bp, base pair; IUCN, The International Union for Conservation of Nature; icipe, International Centre of Insect Physiology and Ecology; ML-EID, Martin Lüscher Emerging Infectious Diseases (Laboratory) Keywords Tick diversity; Rickettsia; Anaplasma; Ehrlichia; Theileria; Coxiella

2017-02-01T00:00:00Z Mwamuye, Micky http://repository.anu.ac.ke/handle/123456789/1215 2026-09-10T08:19:24Z 2020-03-01T00:00:00Z

A review of recent research on Theileria parva: Implications for the infection and treatment vaccination method for control of East Coast fever Mwamuye, Micky The infection and treatment (ITM) live vaccination method for control of Theileria parva infection in cattle is increasingly being adopted, particularly in Maasai pastoralist systems. Several studies indicate positive impacts on human livelihoods. Importantly, the first detailed protocol for live vaccine production at scale has recently been published. However, quality control and delivery issues constrain vaccination sustainability and deployment. There is evidence that the distribution of T. parva is spreading from endemic areas in East Africa, North into Southern Sudan and West into Cameroon, probably as a result of anthropogenic movement of cattle. It has also recently been demonstrated that in Kenya, T. parva derived from cape buffalo can ‘breakthrough’ the immunity induced by ITM. However, in Tanzania, breakthrough has not been reported in areas where cattle co-graze with buffalo. It has been confirmed that buffalo in northern Uganda national parks are not infected with T. parva and R. appendiculatus appears to be absent, raising issues regarding vector distribution. Recently, there have been multiple field population genetic studies using variable number tandem repeat (VNTR) sequences and sequencing of antigen genes encoding targets of CD8+ T-cell responses. The VNTR markers generally reveal high levels of diversity. The antigen gene sequences present within the trivalent Muguga cocktail are relatively conserved among cattle transmissible T. parva populations. By contrast, greater genetic diversity is present in antigen genes from T. parva of buffalo origin. There is also evidence from several studies for transmission of components of stocks present within the Muguga cocktail, into field ticks and cattle following induction of a carrier state by immunization. In the short term, this may increase live vaccine effectiveness, through a more homogeneous challenge, but the long-term consequences are unknown.

2020-03-01T00:00:00Z Mwamuye, Micky M http://repository.anu.ac.ke/handle/123456789/1214 2026-09-10T08:07:17Z 2020-10-01T00:00:00Z

Variant analysis of the sporozoite surface antigen gene reveals that asymptomatic cattle from wildlife-livestock interface areas in northern Tanzania harbour buffalo-derived T. parva Mwamuye, Micky M Buffalo-derived Theileria parva can ‘break through’ the immunity induced by the infection and treatment vaccination method (ITM) in cattle. However, no such ‘breakthroughs’ have been reported in northern Tanzania where there has been long and widespread ITM use in pastoralist cattle, and the Cape buffalo (Syncerus caffer) is also present. We studied the exposure of vaccinated and unvaccinated cattle in northern Tanzania to buffalo-derived T. parva using p67 gene polymorphisms and compared this to its distribution in vaccinated cattle exposed to buffalo-derived T. parva in central Kenya, where vaccine ‘breakthroughs’ have been reported. Additionally, we analysed the CD8+ T cell target antigen Tp2 for positive selection. Our results showed that 10% of the p67 sequences from Tanzanian cattle (n = 39) had a buffalo type p67 (allele 4), an allele that is rare among East African isolates studied so far. The percentage of buffalo-derived p67 alleles observed in Kenyan cattle comprised 19% of the parasites (n = 36), with two different p67 alleles (2 and 3) of presumptive buffalo origin. The Tp2 protein was generally conserved with only three Tp2 variants from Tanzania (n = 33) and five from Kenya (n = 40). Two Tanzanian Tp2 variants and two Kenyan Tp2 variants were identical to variants present in the trivalent Muguga vaccine. Tp2 evolutionary analysis did not show evidence for positive selection within previously mapped epitope coding sites. The p67 data indicates that some ITM-vaccinated cattle are protected against disease induced by a buffalo-derived T. parva challenge in northern Tanzania and suggests that the parasite genotype may represent one factor explaining this. Keywords Theileria parva . p67 . Tp2 . Antigen diversity . Cape Buffalo . Live vaccine

2020-10-01T00:00:00Z Mwamuye, M http://repository.anu.ac.ke/handle/123456789/1213 2026-09-10T06:34:18Z 2022-09-01T00:00:00Z

Incidence of toxigenic Aspergillus and Fusarium species occurring in maize kernels from Kenyan households Mwamuye, M Aspergillus andFusarium are fungal genera that include toxigenic and pathogenic species, able to suffuse farmers’ crops and secrete an array of small molecular weight secondary metabolites which can cause health complications to humans and animals when ingested. In sub-Sahara Africa, contamination and persistence of these fungi is increased by the tropical climatic conditions which are ideal for the fungi to thrive. This study evaluated the incidence, regional distribution and toxigenic potential ofAspergillus andFusarium species occurring in maize kernels from Eastern, Western, Coastal and the Lake Victoria agro-ecological zones of Kenya. Maize kernels were collected from 16 households in each agro-ecological zone. Single spore technique was used to isolate pure cultures ofAspergillus andFusarium which were identified morphologically. Further, molecular analysis was done using the internal transcribed spacer 1 (ITS 1) region of the ribosomal DNA forAspergillus and the translation elongation factor-1 alpha (TEF-1α) forFusarium. The potential of the isolated fungi to produce mycotoxins was probed by polymerase chain reaction (PCR) based on the aflatoxin regulatoryaflaR gene inAspergillus, and the fumonisin backbone structure geneFUM1 inFusarium. Among the potentially aflatoxigenicA. flavus species isolated, 55% were from Eastern, 27% from the Coastal zone, 13% from Lake Victoria zone and 5% from Western Kenya. Among the potentially fumonisin producingF. verticillioides isolated, 45% were from the Lake Victoria agro-ecological zone, 30% were from Western, 15% from Eastern Kenya and 10% from the Coastal agro-ecological zone. This study adds data on potential mycotoxin hotspots in Kenya useful in employing targeted and regional mycotoxin mitigation strategies in efforts to avert future mycotoxicoses outbreaks in Kenya.

2022-09-01T00:00:00Z Jones, Sharon M. Caspi, Itamar Lucas, Charles http://repository.anu.ac.ke/handle/123456789/713 2021-09-22T09:06:01Z 2021-01-01T00:00:00Z

Fibropapillomatosis infection in a population of green turtles at Watamu Bay, Kenya Jones, Sharon M.; Caspi, Itamar; Lucas, Charles Anthropogenic stressors from onshore and offshore activities can act as driving factors of disease for a wide range of marine organisms. Green turtles (Chelonia mydas) are prominently afflicted with a tumour-causing disease known as fibropapillomatosis (FP) caused by the chelonid alphaherpesvirus ChHV5. Previous studies indicate that pathways of FP transmission may be genetic (vertical transmission) or linked to causal factors in a turtle’s environment (horizontal transmission). In this paper patterns of FP prevalence were examined in 10,896 records of green turtles caught or found stranded around Watamu Bay, Kenya, between 2003 – 2020. Findings were focused on locational and seasonal factors that may potentially influence infection. The findings show that FP prevalence varies significantly on an annual basis. Location significantly influenced infection prevalence, with prevalence higher in open ocean sites than sites located within the creek. Infection prevalence was highest at sites around the creek mouth and north of the creek mouth, with both regions exhibiting disparate annual patterns of infection. This paper is the first to examine long-term trends of FP prevalence in-depth in this region and has implications for the health of turtles and marine biota found along the Kenyan coast, and potentially within the wider Western Indian Ocean region. The findings emphasize the need to distinguish the infection pathways of causative agents via: i) further examination of the links between infection and environmental and/or biont community factors; and ii) the collection of data pertinent to the genetic diversity of green turtles and associated ChHV5 viral strains occurring in the Western Indian Ocean.

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