Journal Article Epublish
PubMed: 41174791 DOI: 10.1186/s13071-025-07051-z
Nationwide surveillance detects yellow fever and chikungunya viruses in multiple Aedes mosquito species in Nigeria.
Parasit Vectors 18(1):443
Authors: Udoka C Nwangwu, Harouna Soumare, Judith U Oguzie, William E Nwachukwu, Cosmas O Onwude, Festus A Dogunro, Mawlouth Diallo, Chukwuebuka K Ezihe, Nneka O Agashi, Emelda I Eloy, Stephen O Anokwu, Clementina C Anioke, Linda C Ikechukwu, Chukwuebuka M Nwosu, Oscar N Nwaogo, Ifeoma M Ngwu, Rose N Onyeanusi, Angela I Okoronkwo, Francis U Orizu, Monica O Etiki, Esther N Onuora, Peter C Okeke, Okechukwu C Chukwuekezie, Josephine C Ochu, Anise N Happi, Sulaiman S Ibrahim, Adetifa Ifedayo, Chikwe Ihekweazu, Christian T Happi
Affiliations
- National Arbovirus and Vectors Research Centre (NAVRC), Enugu, Enugu State, Nigeria.
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Osun State, Nigeria.
- Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Osun State, Nigeria.
- Nigeria Centre for Disease Control, Abuja, FCT, Nigeria.
- National Arbovirus and Vectors Research Centre (NAVRC), Enugu, Enugu State, Nigeria.
- Medical Zoology Center, Institut Pasteur de Dakar, Dakar, Senegal.
- Malaria Consortium, Abuja, FCT, Nigeria.
- Department of Parasitology and Entomology, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria.
- Opec Research Consult, Awka, Anambra State, Nigeria.
- Department of Biochemistry, Bayero University, Kano, Kano State, Nigeria.
- Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon.
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Osun State, Nigeria.
- Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Osun State, Nigeria.
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA.
Abstract
BACKGROUND
Since the reemergence of yellow fever in 2017, the Nigeria Centre for Disease Control (NCDC) has been coordinating responses to local outbreaks with the support of the World Health Organization (WHO). The National Arbovirus and Vectors Research Centre (NAVRC) has been implementing targeted vector control interventions to mitigate the occurrence of these outbreaks. This study sought to identify the vectors driving yellow fever (YF) transmission and other public health arboviruses and their distribution across Nigeria.
METHODS
Between 2017 and 2020, larvae, pupae, and adult mosquitoes were collected, largely targeting Aedes Stegomyia mosquitoes, in observational, analytical, and cross-sectional surveys conducted in sixteen YF outbreak states of Nigeria. Adult mosquitoes (field-collected or reared from immature stages) were morphologically identified, and arboviruses were detected using reverse transcription quantitative polymerase chain reaction (RT-qPCR).
RESULTS
Seven different Aedes mosquito species were found in 11 of the 16 states surveyed, with mosquitoes from nine states found infected with arboviruses. Aedes aegypti was the predominant species (51%), whereas Aedes africanus was the least common species (0.2%). Yellow fever virus (YFV) was detected in 33 (~ 26%) out of the 127 Aedes mosquito pools, with minimum infection rates in the ranges of 0.9 (Ae. circumluteolus) to 62.5 (Ae. luteocephalus) per 1000 mosquitoes. In addition to YFV, the chikungunya virus (CHIKV) was found in nine pools, with minimum infection rates ranging from 1.6 (Ae. aegypti) to 62.5 (Ae. luteocephalus) per 1000 mosquitoes. Except for Ae. africanus, all the Aedes species tested positive for at least one arbovirus. YFV-positive pools were found in six Aedes species (Ae. aegypti, Ae. albopictus, Ae. simpsoni complex, Ae. luteocephalus, Ae. vittatus, and Ae. circumluteolus), while CHIKV-positive pools were recorded in only two Aedes species (Ae. aegypti and Ae. luteocephalus). There was co-detection of YFV and CHIKV in Ae. luteocephalus (Benue State). Edo State had the most positive pools (16), while Nasarawa, Imo, and Anambra states had the least (one positive pool). Breteau and house indices were higher than the standard WHO transmission thresholds in all but one state, suggesting high risk for arbovirus transmission.
CONCLUSIONS
In Nigeria, there is substantial risk of arbovirus transmission by Aedes mosquitoes, with YFV posing a large threat. This risk is heightened by the fact that YFV and CHIKV have been detected concurrently in vectors across outbreak locations. There is an urgent need to step up arbovirus surveillance and vector control activities across the country.
MeSH
Disease Outbreaks, Arboviruses, Chikungunya Virus, Viruses, Yellow Fever, Parasites, Infections