Experimental Lagos bat virus infection in straw-colored fruit bats: A suitable model for bat rabies in a natural reservoir species

Rabies is a fatal neurologic disease caused by lyssavirus infection. Bats are important natural reservoir hosts of various lyssaviruses that can be transmitted to people. The epidemiology and pathogenesis of rabies in bats are poorly understood, making it difficult to prevent zoonotic transmission. To further our understanding of lyssavirus pathogenesis in a natural bat host, an experimental model using straw-colored fruit bats (Eidolon helvum) and Lagos bat virus, an endemic lyssavirus in this species, was developed. To determine the lowest viral dose resulting in 100% productive infection, bats in five groups (four bats per group) were inoculated intramuscularly with one of five doses, ranging from 10^0.1 to 10^4.1 median tissue culture infectious dose (TCID₅₀). More bats died due to the development of rabies after the middle dose (10^2.1 TCID₅₀, 4/4 bats) than after lower (10^1.1, 2/4; 10^1.1, 2/4) or higher (10^3.1, 2/4; 10^4.1, 2/4) doses of virus. In the two highest dose groups, 4/8 bats developed rabies. Of those bats that remained healthy 3/4 bats seroconverted, suggesting that high antigen loads can trigger a strong immune response that abrogates a productive infection. In contrast, in the two lowest dose groups, 3/8 bats developed rabies, 1/8 remained healthy and seroconverted and 4/8 bats remained healthy and did not seroconvert, suggesting these doses are too low to reliably induce infection. The main lesion in all clinically affected bats was meningoencephalitis associated with lyssavirus-positive neurons. Lyssavirus antigen was detected in tongue epithelium (5/11 infected bats) rather than in salivary gland epithelium (0/11), suggesting viral excretion via the tongue. Thus, intramuscular inoculation of 10^2.1 TCID₅₀ of Lagos bat virus into straw-colored fruit bats is a suitable model for lyssavirus associated bat rabies in a natural reservoir host, and can help with the investigation of lyssavirus infection dynamics in bats.     

Ticks associated with wild mammals in Ghana

The host ranges of a collection of 21 tick species found on wild mammals in the savanna, forests and coastal zone of Ghana suggested that most species were adapted to feeding mainly on host species within a single mammalian order, i.e. on artiodactyls (bovids/suids), carnivores, rodents or pholidotes (pangolins). Only a few species were dispersed evenly across a range of orders. Seven out of ten of the most common ticks on forest mammals were significantly associated with a particular host species or a group of closely related host species, which could be viewed as their major host or hosts, but they were also recorded much less frequently on a wide range of host species. Two other species were confined to their major hosts. Only one species appeared to be widely dispersed on forest mammals and to lack a particular major host. The majority of tick species therefore occurred on hosts with very distinctive biological, behavioural and ecological characteristics. The study provided no evidence to support the view that host specificity is an artefact of sampling. Finding that the tick species on Ghanaian wild mammals occurred on particular hosts, as well as in distinct habitats, indicated that tick-host associations are important for tick survival and confirmed the importance of climate and vegetation in tick distribution.     

An updated list of the ticks of Ghana and an assessment of the distribution of the ticks of Ghanaian wild mammals in different vegetation zones

Twenty one species of ticks belonging to five genera of the family Ixodidae (Order Acari, sub-order Ixodida) - Amblyomma, Haemaphysalis, Hyalomma, Ixodes and Rhipicephalus (including the sub-genus Rhipicephalus (Boophilus)) - were collected from 1260 mammals, representing 29 species, 14 families and 6 orders, in four vegetation zones in Ghana during the period 1971-1978. Four other species were collected from humans in 1977. In all, eight species appeared to be new records for Ghana: Amblyomma tholloni Neumann; Dermacentor circumguttatus Neumann; Haemaphysalis houyi Nuttall & Warburton; Ixodes loveridgei Arthur; Ixodes oldi Nuttall; Ixodes vanidicus Schultze; Rhipicephalus complanatus Neumann; Rhipicephalus cuspidatus Neumann. The updated list of tick species in Ghana given here includes 41 species of ixodid ticks and four species of argasid ticks. Most species have been found in neighbouring regions of West Africa but 56 of the 121 different combinations of ixodid tick species and host species found in the collection described here have not apparently been reported before. The new combinations recorded here bring the total number of different combinations of ixodid tick species and mammalian host species now reported in Ghana to 151. The tick species found on wild mammals in Ghana mostly differed from those reported from domestic stock by other authors. The data showed that different tick species occurred in different vegetation zones and that most species displayed a pronounced preference for certain groups of related host species. Some tick species were found in the savanna feeding mainly on large bovids and/or suids; others were found in forests feeding mainly on small bovids, large rodents or small carnivores.     

Functionally distinct roles for TET-oxidized 5-methylcytosine bases in somatic reprogramming to pluripotency

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The Muni-Pomadze Ramsar site

The Coastal Wetlands Management Project (CWMP), funded by the Global Environment Facility and implemented by the Ghana Wildlife Department, seeks to preserve the ecological integrity of coastal lagoons that serve as important sites for migratory waterbirds. This report describes the geomorphology, hydrology, soils, water chemistry, and vegetation of the Muni-Pomadze Ramsar site. Muni lagoon is a saline, shallow water lagoon separated from the sea by a sand bar which may be breached occasionally. The bulk of the rainfall in the catchment evaporates or flows as surface runoff into three streams that empty into Muni lagoon. Open water in the lagoon varies seasonally from 100 ha in the dry season to over 1000 ha in the wet season. The natural flora of the site can be divided into four main types; flood plain (including mangrove and wetland vegetation), dune vegetation, riverine vegetation, and terrestrial vegetation on elevated ground. The latter consists of a combination of grasslands, thickets, and Eucalyptus plantations. Fifty-three percent of the site is classified as natural vegetation. An additional 32.5% is agricultural land and 12.6% is residential area for the 11 communities within the site. The main source of employment are farming or fishing. The area surrounding Muni lagoon is used extensively for bushmeat hunting and as the tribal hunting grounds of the Efutu people. Apart from the global importance of the Muni-Pomadze site for biodiversity, management of the site is further justified by its considerable potential for development as an income-generating and educational nature reserve with an eco-cultural theme, managed by the local communities in partnership with the governmental and non-governmental conservation agencies.     

Waterbird and wetland research and conservation in Ghana: a ten year perspective

Ntiamoa-Baidu, Y. & Gordon, C. 2000. Waterbird & wetland research and conservationin Ghana: a ten year perspective. Ostrich 71 (1 & 2): 95.

The study outlines the evolution of ecological research on waterbirds and wetland conservation initiatives in Ghana over a ten year period, 1986–1996. A survey of waterbird populations was initiated in the country in October 1985, through a collaborative effort between the Ghana Government, the Royal Society for the Protection of Birds (RSPB) UK and BirdLife International. These studies identified key wetland sites on the Ghana coast which have been regularly monitored up to today, thus providing the most comprehensive long-term data on waterbird populations within the West African sub-region. Over the ten year period the simple waterbird counting has led to comprehensive ecological research on waterbirds, the establishment of a national Bird Ringing Scheme and the development of a core of trained ornithologists in Ghana. In terms of conservation action, the data provided the justification for designation of the five most important coastal wetland sites as Ramsar sites and the establishment of the Ghana Coastal Wetlands Management Project (CWMP) to manage the sites. The management strategy adopted seeks not only to maintain the ecological integrity of the wetlands, but more importantly, to enhance the benefits derived from wetlands by local communities and improve the quality of life for the coastal people. Management actions are guided by a multi-disciplinary research on the coastal wetland ecosystem, which incorporates biological, physico-chemical and socio-economic dimensions. The large body of environmental data accumulated during the initial stages of the CWMP provide a solid base for the monitoring of the ecological character of the wetlands and the evaluation of management activities. The events in Ghana clearly demonstrate the value of a strong scientific data-base in our efforts to promote conservation of Africa's wetlands and wetland resources.     

Characteristics and Risk Perceptions of Ghanaians Potentially Exposed to Bat-Borne Zoonoses through Bushmeat

EcoHealth - Emerging zoonotic pathogens from wildlife pose increasing public health threats globally. Bats, in particular, host an array of zoonotic pathogens, yet there is little research on how...     

Compromised store-operated Ca2+ entry in aged skeletal muscle

In aged skeletal muscle, changes to the composition and function of the contractile machinery cannot fully explain the observed decrease in the specific force produced by the contractile machinery that characterizes muscle weakness during aging. Since modification in extracellular Ca²⁺ entry in aged nonexcitable and excitable cells has been recently identified, we evaluated the functional status of store-operated Ca²⁺ entry (SOCE) in aged mouse skeletal muscle. Using Mn²⁺ quenching of Fura-2 fluorescence and confocal-microscopic imaging of Ca²⁺ movement from the transverse tubules, we determined that SOCE was severely compromised in muscle fibers isolated from aged mice (26–27 months) as compared with those from young (2–5 months) mice. While reduced SOCE in aged skeletal muscle does not appear to result from altered expression levels of STIM1 or reduced expression of mRNA for Orai, this reduction in SOCE is mirrored in fibers isolated from young mice null for mitsugumin-29, a synaptophysin-related protein that displays decreased expression in aged skeletal muscle. Our data suggest that decreased mitsugumin-29 expression and reduced SOCE may contribute to the diminished intracellular Ca²⁺ homeostatic capacity generally associated with muscle aging.