Evolutionary History of Rabies in Ghana

Abstract

Rabies virus (RABV) is enzootic throughout Africa, with the domestic dog (Canis familiaris) being the principal vector. Dog rabies is estimated to cause 24,000 human deaths per year in Africa, however, this estimate is still considered to be conservative. Two sub-Saharan African RABV lineages have been detected in West Africa. Lineage 2 is present throughout West Africa, whereas Africa 1a dominates in northern and eastern Africa, but has been detected in Nigeria and Gabon, and Africa 1b was previously absent from West Africa. We confirmed the presence of RABV in a cohort of 76 brain samples obtained from rabid animals in Ghana collected over an eighteen-month period (2007–2009). Phylogenetic analysis of the sequences obtained confirmed all viruses to be RABV, belonging to lineages previously detected in sub-Saharan Africa. However, unlike earlier reported studies that suggested a single lineage (Africa 2) circulates in West Africa, we identified viruses belonging to the Africa 2 lineage and both Africa 1 (a and b) sub-lineages. Phylogeographic Bayesian Markov chain Monte Carlo analysis of a 405 bp fragment of the RABV nucleoprotein gene from the 76 new sequences derived from Ghanaian animals suggest that within the Africa 2 lineage three clades co-circulate with their origins in other West African countries. Africa 1a is probably a western extension of a clade circulating in central Africa and the Africa 1b virus a probable recent introduction from eastern Africa. We also developed and tested a novel reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assay for the detection of RABV in African laboratories. This RT-LAMP was shown to detect both Africa 1 and 2 viruses, including its adaptation to a lateral flow device format for product visualization. These data suggest that RABV epidemiology is more complex than previously thought in West Africa and that there have been repeated introductions of RABV into Ghana. This analysis highlights the potential problems of individual developing nations implementing rabies control programmes in the absence of a regional programme.

Is Predominant Clonal Evolution a Common Evolutionary Adaptation to Parasitism in Pathogenic Parasitic Protozoa, Fungi, Bacteria, and Viruses?

“…The rabies virus (RABV) exhibits two distinct lineages in West Africa that shows partial allopatry, but can be found sympatrically (Hayman et al, 2011). At the level of the whole species, three 'clades' (near-clades) can be identified (I, South East Asia; II, worldwide; III, only bats and raccoons in North and South America).…”

Reproductive clonality of pathogens: A perspective on pathogenic viruses, bacteria, fungi, and parasitic protozoa

“…Widespread and stable clustering is found in viruses, particularly in RNA viruses, when taking into account the extremely rapid turnover of their genotypes. Structuring is clear in (i) RNA viruses: Chikungunya virus (169), coronaviruses (171), dengue virus (172-174), Ebola virus (175), Enterovirus echovirus (176), hepatitis C virus (177,179), hepatitis E virus (180), HIV (170,181), rabies virus (185,186), and West Nile virus (187,188); and (ii) DNA viruses: hepatitis B virus (164), Varicella zoster virus (168), and variola virus (167).…”

Modelling of Rabies Transmission Dynamics Using Optimal Control Analysis

“…Rabies is an infection that mostly affects the brain of an infected animal or individual, caused by viruses belonging to the genus Lyssavirus of the family Rhabdoviridae and order Mononegavirales [1,2]. This disease has become a global threat and it is also estimated that rabies occurs in more than 150 countries and territories [2].…”