Widespread arenavirus occurrence and seroprevalence in small mammals, Nigeria

• Published in: Parasites & vectors Vol. 11; no. 1; p. 416
• Main Authors: Olayemi, Ayodeji, Oyeyiola, Akinlabi, Obadare, Adeoba, Igbokwe, Joseph, Adesina, Adetunji Samuel, Onwe, Francis, Ukwaja, Kingsley Nnanna, Ajayi, Nnennaya Anthony, Rieger, Toni, Günther, Stephan, Fichet-Calvet, Elisabeth
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 13.07.2018; BioMed Central; BMC
• Subjects: Animals; Antibodies; Antibodies, Viral - blood; Arenaviridae; Arenaviridae Infections - blood; Arenaviridae Infections - epidemiology; Arenaviridae Infections - veterinary; Arenaviridae Infections - virology; Arenavirus - immunology; Arenavirus - physiology; Arenaviruses; Crocidura; Deoxyribonucleic acid; Detection; Disease Reservoirs - virology; DNA; DNA sequences; DNA sequencing; Endemic species; Epidemics; Fever; Geographical distribution; Geography; Host; Identification and classification; IgG antibody; Immunofluorescence; Immunoglobulin G; Insectivora - virology; Lassa fever; Lassa virus - immunology; Lassa virus - physiology; Mammals; Mastomys erythroleucus; Mastomys natalensis; Medical research; Methods; Mice; Mus baoulei; Mus minutoides; Mus musculus; Nigeria - epidemiology; Nucleotide sequence; PCR; Polymerase chain reaction; Populations; Praomys daltoni; Praomys misonnei; Prevalence; Prevalence studies (Epidemiology); Rats; Rattus rattus; Reverse Transcriptase Polymerase Chain Reaction; RNA, Viral - genetics; Rodent Diseases - blood; Rodent Diseases - epidemiology; Rodent Diseases - virology; Rodentia; Rodentia - virology; Rodents; Seasons; Seroepidemiologic Studies; Serology; Small mammals; Statistical analysis; Vectors (Biology); Viruses; Zoonoses; Zoonotic virus; Nigeria; Zambia; West Africa; Africa; Lassa fever; Host; Serology; Rodents; Zoonotic virus
• ISSN: 1756-3305; 1756-3305
• DOI: 10.1186/s13071-018-2991-5

Lassa fever, killing thousands of people annually, is the most reported viral zoonotic disease in Nigeria. Recently, different rodent species carrying diverse lineages of the Lassa virus (LASV) in addition to a novel Mobala-like genetic sequence were detected within the country. Here, screening 906 small mammal specimens from 11 localities for IgG antibodies and incorporating previous PCR detection data involving the same populations, we further describe arenavirus prevalence across Nigeria in relation to host species and geographical location. Small mammals were trapped during the period 2011-2015 according to geographical location (endemic and non-endemic zones for Lassa fever), season (rainy and dry seasons between 2011 and 2012 for certain localities) and habitat (indoors, peridomestic settings and sylvatic vegetation). Identification of animal specimens from genera such as Mastomys and Mus (Nannomys) was assisted by DNA sequencing. Small mammals were tested for LASV IgG antibody using an indirect immunofluorescence assay (IFA). Small mammals were infected in both the endemic and non-endemic zones for Lassa fever, with a wider range of species IgG-positive (n = 8) than those which had been previously detected to be PCR-positive (n = 3). IgG-positive species, according to number of infected individuals, were Mastomys natalensis (n = 40), Mastomys erythroleucus (n = 15), Praomys daltoni (n = 6), Mus baoulei (n = 5), Rattus rattus (n = 2), Crocidura spp. (n = 2), Mus minutoides (n = 1) and Praomys misonnei (n = 1). Multimammate mice (Mastomys natalensis and M. erythroleucus) were the most ubiquitously infected, with animals testing positive by either PCR or IgG in 7 out of the 11 localities sampled. IgG prevalence in M. natalensis ranged from 1% in Abagboro, 17-36 % in Eguare Egoro, Ekpoma and Ngel Nyaki, up to 52 % in Mayo Ranewo. Prevalence according to locality, season and age was not, however, statistically significant for M. natalensis in Eguare Egoro and Ekpoma, localities that were sampled longitudinally. Overall, our study demonstrates that arenavirus occurrence is probably more widely distributed geographically and in extent of host taxa than is currently realized. This expanded scope should be taken into consideration in Lassa fever control efforts. Further sampling should also be carried out to isolate and characterize potential arenaviruses present in small mammal populations we found to be seropositive.