Species composition and risk of transmission of some Aedes-borne arboviruses in some sites in Northern Ghana

Abstract

Aedes-borne viral diseases mainly Yellow Fever (YF), Dengue (DEN), Zika (ZIK) and Chikungunya (CHK) have contributed to many deaths’ in the world especially in Africa. There have been major outbreaks of these diseases in West Africa. Although, YF outbreaks have occurred in Ghana over the years, no outbreak of DEN, ZIK and CHK has been recorded. However, the risk of outbreak is high due to its proximity to West African countries where outbreaks have been recently been recorded. This study surveyed the mosquito fauna to assess the risk of transmission of Yellow fever (YFV), Dengue (DENV), Chikungunya (CHKV) and Zika (ZIKV) viruses in Larabanga and Mole Game Reserve areas in Northern Ghana. The immature and adult stages of Aedes mosquitoes were collected from Larabanga and Mole Game Reserve area. There was a significant (P>0.001) number of mosquitoes collected during the rainy season than the dry season. A total of 1,930 Aedes mosquitoes were collected during the rainy season and morphologically identified. Of these, 1,915 (99.22%) were Aedes aegypti and 15 (0.22%) were Aedes vittatus. During the dry season, 27 Ae. aegypti mosquitoes were collected. A total of 415 Ae. aegypti mosquitoes were molecularly identified to subspecies level of which Ae. (Ae) aegypti aegypti was the predominant subspecies. Both Ae. aegypti aegypti and Ae aegypti formosus exist in sympatry in the area. All Aedes pools (75) were negative for DENV, ZIKV and CHKV when examined by RT- PCR. Three Larval indices namely House Index, HI (percentage of houses positive for Aedes larvae or pupae), Container Index, CI (the percentage of containers positive for Aedes larvae or pupae) and Breteau Index, BI (number of positive containers per 100 houses inspected) were assessed as a measure for risk of transmission in the study area. The HI, CI and BI for both sites were as follows; Mole Game Reserve (HI, 42.1%, CI, 23.5% and BI, 100 for rainy season and 0 for all indices for dry season) and Larabanga (39%, 15.5% and 61 for rainy season and 2.3%, 1.3% and 2.3 for dry season). The spatial distribution of Aedes breeding sites in both areas indicated that Aedes larvae were breeding in areas with close proximity to humans. Lorry tires were the main source of Aedes larvae in all the study areas. Information about the species composition and the potential role of Aedes mosquitoes in future outbreaks of the diseases that they transmit is needed to design efficient surveillance and vector control tools.

Ecology, Distribution and Risk of Transmission of Viral Haemorrhagic Fevers by <i>Aedes</i> Mosquitoes around the Port Areas of Tema in Southern Ghana

“…Temperature, relative humidity and nutrients source is known to contribute to mosquito abundance during rainy season, while absence of all or any of these components and high or extreme temperature decrease mosquito breeding or abundance in the dry season [33]. In this study, high abundance of Aedes immature stages were found in the rainy season than the dry season as previously reported in other studies in northern and southern Ghana [16] [24] [25]. However, another study in northern Ghana found high larval indices in the dry season than the rainy season and ascribed the reason that many people tend to store water much longer during the dry season than the rainy season [34].…”

“…Different species of Aedes mosquitoes, which are potential vectors for yellow fever, are already known to be distributed all over Ghana as reported by various studies in different parts of the country [11] [16] [24] [25]. The study revealed the presence of only one distinct Aedes species and other mosquito species (Culex spp.…”

Whole genome sequencing unravels cryptic circulation of divergent dengue virus lineages in the rainforest region of Nigeria

“…The intense rainfall and flooding activities in the coastal state of Lagos may disrupt the stability of the mosquito eggs and larvae [ 54 ], whereas the forested regions provide more vegetation cover and high relative humidity to support mosquito breeding. Aedes aegypti , the primary vector for DENV, thrives well in urban and semi-urban environments, breeding in stagnant water and hollow containers [ 55 ]. The presence and distribution of Aedes spp.…”

Arbovirus Epidemiology: The Mystery of Unnoticed Epidemics in Ghana, West Africa

“…africanus may have been the vector [ 21 ]. Later, other entomological investigations were done to assess the status and risk of transmission of mosquito-borne viruses [ 44 , 45 , 46 ]. Overall, no arbovirus was detected in any of these entomological studies.…”