Ecology of Ticks (Ixodidae) on Cattle within Main Campus of the University of Abuja, Nigeria

A survey was conducted using standard parasitological procedures to determine the ecology of ticks on the cattle within the main campus of the University of Abuja, Nigeria. The tick specie identified were Amblyomma variegatum, Amblyomma hebraeum, 0rnithodorus moubata complex, Hyalomma truncatum, Hyalomma rufipies, Rhipicephalus decoloratus, Phipicephalus appendiculatus, and Boophilus microplus. Of the 100 cattle examined. 47(47%) of the tick examined was found on the male cow and 53(53%) were found on the female cow. In addition, 23(23%) of the observed tick are found on the leg, 20(20%) are found in the anus, 20(20%) are found on the udder, 14(14%) are found on the back while 23(23%) of the ticks are found in the ear. 31(31%) of the observed ticks were found on the bunaj specie, 24(24%) of the ticks on the Gudali, 24(24%) of the observed ticks on the Rahaji specie and 21(21%) on the wadara specie. Amblyomma hebraeum, Ornithodorus moubata Complex and Rhipicephalus dicoloratus were found more dominantly on Bunaj breed (42.9%, 55.6% and 42.9% respectively), Amblyomma variegatum and Phipicephalus appendiculatus was observed to be more dominant on Rahaji breed (infesting 33.3% and 66.7% respectively), Boophylus microplus and Hyalomma rufipe were found dominant on wadara (30% and 50% respectively). There is need to help establish baseline information on ticks ecology and occurrence in the study area which would consequently lead to increased public awareness especially to the herdsmen and in avoiding tick borne diseases, also to help in vector control formulation and to prevent the herdsmen of suffering from low productivity due to the presence of ticks, thereby leading to various weaknesses, diseases and sometimes death of the cattle. Owing to this, this study did not only identify the tick species infesting cattle but also examined the host-parasite ecology of ticks on cattle within the main campus of the University of Abuja, Nigeria.

Rickettsia africae: identifying gaps in the current knowledge on vector-pathogen-host interactions

Rickettsia africae is a bacterium of zoonotic importance, which causes African tick bite fever (ATBF) in humans. This pathogen is transmitted by ticks of the genus Amblyomma, with Amblyomma hebraeum and Amblyomma variegatum being the major vectors. Tick species other than the above-mentioned have also been reported to carry R. africae DNA. There is scarcity of information on the epidemiology of this pathogen, yet several cases have been recorded in foreign travellers who visited endemic areas, especially southern Africa. The disease has rarely been described in people from endemic regions. The aim of this study was to discuss the information that is currently available on the epidemiology of R. africae, highlighting the gaps in this field. Furthermore, ATBF cases, clinical signs and the locations where the cases occurred are also listed in this review.

A Pilot Study on the Microbiome of Amblyomma hebraeum Tick Stages Infected and Non-Infected with Rickettsia africae

Variation in tick microbiota may affect pathogen acquisition and transmission but for many vector species, including Amblyomma hebraeum, components and determinants of the microbiome are unidentified. This pilot study aimed to determine baseline microbial community within A. hebraeum nymphs infected- and non-infected with Rickettsia africae from the environment, and within adult ticks infected- and non-infected with R. africae collected from cattle sampled from two locations in the Eastern Cape province of South Africa. Adult A. hebraeum ticks (N = 13) and A. hebraeum nymph (N = 15) preliminary screened for R. africae were randomly selected and subjected to Illumina sequencing targeting the v3–v4 hypervariable regions of the 16S rRNA gene. No significant difference in microbial community composition, as well as rarefied OTU richness and diversity were detected between adults and nymphs. Nymphs showed a higher richness of bacterial taxa indicating blood-feeding could have resulted in loss of microbial diversity during the moulting stage from nymph to adult. Core OTUs that were in at least 50% of nymphs and adults negative and positive for Rickettsia at 1% minimum relative abundance were Rickettsia, Coxiella and Ruminococcaceae UCG-005 with a single genus Arsenophonus occurring only in nymphs negative for Rickettsia. Ehrlichia spp. was present in only four nymphal ticks positive for Rickettsia. Interestingly, Rickettsia aeschlimannii was found in one nymph and one adult, indicating the first ever detection of the species in A. hebraeum. Furthermore, A. hebraeum harboured a Coxiella-like endosymbiont, which should be investigated further as Coxiella may affect the viability and transmission of other organisms.

Spatial clustering of fourteen tick species across districts of Zimbabwe

Background Ticks transmit several diseases that result in high morbidity and mortality in livestock. Tick-borne diseases are an economic burden that negatively affect livestock production, cost countries billions of dollars through vaccine procurement and other disease management efforts. Thus, understanding the spatial distribution of tick hotspots is critical for identifying potential areas of high tick-borne disease transmission and setting up priority areas for targeted tick disease management. In this study, optimised hotspot analysis was applied to detect hotspots and coldspots of 14 common tick species in Zimbabwe. Data on the spatial distribution of tick species were obtained from the Epidemiology Unit of the Division of Veterinary Field Services of Zimbabwe. Results A total of 55,133 ticks were collected with Rhipicephalus decoloratus being the most common species (28.7%), followed by Amblyomma hebraeum (20.6%), and Rhipicephalus sanguineus sensu lato (0.06%) being the least common species. Results also showed that tick hotspots are species-specific with particular tick species occupying defined localities in the country. For instance, Amblyomma variegatum, Rhipicephalus appendiculatus, Rhipicephalus decoloratus, Rhipicephalus compostus, Rhipicephalus microplus, Rhipicephalus pravus, and Rhipicephalus simus were concentrated in the north and north eastern districts of the country. In contrast, Amblyomma hebraeum, Hyalomma rufipes, Hyalomma trancatum and Rhipicephalus evertsi evertsi were prevalent in the southern districts of Zimbabwe. Conclusion The occurrence of broadly similar hotspots of several tick species in different districts suggests presence of spatial overlaps in the niche of the tick species. As ticks are vectors of several tick-borne diseases, there is high likelihood of multiple disease transmission in the same geographic region. This study is the first in Zimbabwe to demonstrate unique spatial patterns in the distribution of several tick species across the country. The results of this study provide an important opportunity for the development of spatially-targeted tick-borne disease management strategies.

Presence and Persistence of Amblyomma Hebraeum Augments the Burden of Heartwater in the Southern District of Botswana

BACKGROUNDHeartwater is a tick-borne, haemoparasitic disease that has the potential to limit the growth of agro-businesses in Botswana. This threat to national food security is attributed to low production and mortality of livestock in subsistence farming of small stock than in commercial farms. This study gives a view of the epidemiological burden of heartwater in Botswana. METHODSFeeding ticks on livestock kept in four Southern sub-districts of Botswana were identified through morphological and molecular analysis. Farmers were interviewed on the management of the heartwater burden within their respective sub-districts. Veterinary clinical case reports were collected to assess the frequency of cases across the Southern District of Botswana. RESULTSOutcomes of the study revealed; a wide distribution of Amblyomma hebraeum in all four studied sub-districts, gradual annual increase in heartwater cases in Moshupa sub-district and indication of increased impact on indigenous caprine species despite the effort to control vectors by 63% of interviewed farmers. CONCLUSIONAmblyomma hebraeum, the principal vector of Ehrlichia ruminantium in Southern Africa is widely distributed in the Southern District of Botswana and thus poses a challenge to livestock productivity in this district and, perhaps, elsewhere in the country where the tick infests livestock. There is therefore a need to re-examine the existing tick control interventions with an intention to reduce the heartwater disease burden particularly in sheep and goats.

Presence and Persistence of Amblyomma Hebraeum Augments the Burden of Heartwater in the Southern District of Botswana

BACKGROUNDHeartwater is a tick-borne, haemoparasitic disease that has the potential to limit the growth of agro-businesses in Botswana. This threat to national food security is attributed to low production and mortality of livestock in subsistence farming of small stock than in commercial farms. This study gives a view of the epidemiological burden of heartwater in Botswana. METHODSFeeding ticks on livestock kept in four Southern sub-districts of Botswana were identified through morphological and molecular analysis. Farmers were interviewed on the management of the heartwater burden within their respective sub-districts. Veterinary clinical case reports were collected to assess the frequency of cases across the Southern District of Botswana. RESULTSOutcomes of the study revealed; a wide distribution of Amblyomma hebraeum in all four studied sub-districts, gradual annual increase in heartwater cases in Moshupa sub-district and indication of increased impact on indigenous caprine species despite the effort to control vectors by 63% of interviewed farmers. CONCLUSIONAmblyomma hebraeum, the principal vector of Ehrlichia ruminantium in Southern Africa is widely distributed in the Southern District of Botswana and thus poses a challenge to livestock productivity in this district and, perhaps, elsewhere in the country where the tick infests livestock. There is therefore a need to re-examine the existing tick control interventions with an intention to reduce the heartwater disease burden particularly in sheep and goats.