TY - JOUR
T1 - A countrywide molecular survey leads to a seminal identification of the invasive cattle tick Rhipicephalus (Boophilus) microplus in Cameroon, a decade after it was reported in Cote d'Ivoire
AU - Silatsa, Barberine A.
AU - Kuiate, Jules Roger
AU - Njiokou, Flobert
AU - Simo, Gustave
AU - Feussom, Jean Marc K.
AU - Tunrayo, Alabi
AU - Amzati, Gaston S.
AU - Bett, Bernard
AU - Bishop, Richard
AU - Githaka, Naftaly
AU - Opiyo, Stephen O.
AU - Djikeng, Appolinaire
AU - Pelle, Roger
N1 - Funding Information:
We gratefully acknowledge the financial support provided to the Biosciences eastern and central Africa - International Livestock Research Institute (BecA-ILRI) Hub, Nairobi by the Australian Agency for International Development (AusAID) through a partnership between Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) and the BecA-ILRI Hub ; and by the Syngenta Foundation for Sustainable Agriculture (SFSA) ; the Bill & Melinda Gates Foundation (BMGF) ; and the Swedish Ministry of Foreign Affairs through the Swedish International Development Agency (SIDA) , which made this work possible. BA was a recipient of an Africa Biosciences Challenge Fund (ABCF) Fellowship under the BMGF Grant Number OPP1075938 . This research was also supported by the German Academic Exchange Service (DAAD) Special Initiative SFBFR, 2015 ( 57220758 ).
Publisher Copyright:
© 2019 The Authors
Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2019/4/1
Y1 - 2019/4/1
N2 - The cattle tick Rhipicephalus microplus is the most important arthropod vector of livestock diseases globally. Since its introduction in West Africa a decade ago, it has been reported in Ivory Coast, Benin, Togo, Mali, Burkina Faso and Nigeria with potentially far-reaching adverse impacts on the livestock sector in the region. Cameroon is located on a major route for transboundary cattle trade between Central and West Africa and it is therefore at risk from R. microplus invasion. This study investigated the occurrence of R. microplus in Cameroon, the genetic polymorphism of the tick and population structure of isolates from different regions of the country to provide data that underpin the design of future vector control programs. A cross-sectional survey was conducted in which ticks were collected from cattle at 54 sites across the five Agroecological zones (AEZs) within Cameroon. Tick identity (sex and species) was assigned using taxonomic keys. Species identity was confirmed through amplification and sequencing of the mitochondrial COI and 16S rRNA genes. A total of 7091 ticks were collected out of which 1112 (15.6%) were morphologically identified as R. microplus. The presence of R. microplus was confirmed in 4 out of 5 agroecological zones. Only two haplotypes were identified by both COI and 16S rRNA genes, indicating a very low divergence in the genetic structure of the R. microplus population in Cameroon. 16S rRNA sequence analysis revealed a new haplotype specific to Cameroon. Phylogenetic trees revealed that all isolates of R. microplus from Cameroon were grouped into the previously described Africa/Americas clade. Application of a niche modelling algorithm to R. microplus distribution in Cameroon predicted that suitable habitat for the tick extended into southern Nigeria. This study demonstrated for the first time the presence of R. microplus in Cameroon. Genetic diversity tests indicate that the tick has not evolved significantly since the initial introduction to West Africa. We suggest further longitudinal studies to better define the spatial and temporal expansion of the range of the tick and the drivers of this spread.
AB - The cattle tick Rhipicephalus microplus is the most important arthropod vector of livestock diseases globally. Since its introduction in West Africa a decade ago, it has been reported in Ivory Coast, Benin, Togo, Mali, Burkina Faso and Nigeria with potentially far-reaching adverse impacts on the livestock sector in the region. Cameroon is located on a major route for transboundary cattle trade between Central and West Africa and it is therefore at risk from R. microplus invasion. This study investigated the occurrence of R. microplus in Cameroon, the genetic polymorphism of the tick and population structure of isolates from different regions of the country to provide data that underpin the design of future vector control programs. A cross-sectional survey was conducted in which ticks were collected from cattle at 54 sites across the five Agroecological zones (AEZs) within Cameroon. Tick identity (sex and species) was assigned using taxonomic keys. Species identity was confirmed through amplification and sequencing of the mitochondrial COI and 16S rRNA genes. A total of 7091 ticks were collected out of which 1112 (15.6%) were morphologically identified as R. microplus. The presence of R. microplus was confirmed in 4 out of 5 agroecological zones. Only two haplotypes were identified by both COI and 16S rRNA genes, indicating a very low divergence in the genetic structure of the R. microplus population in Cameroon. 16S rRNA sequence analysis revealed a new haplotype specific to Cameroon. Phylogenetic trees revealed that all isolates of R. microplus from Cameroon were grouped into the previously described Africa/Americas clade. Application of a niche modelling algorithm to R. microplus distribution in Cameroon predicted that suitable habitat for the tick extended into southern Nigeria. This study demonstrated for the first time the presence of R. microplus in Cameroon. Genetic diversity tests indicate that the tick has not evolved significantly since the initial introduction to West Africa. We suggest further longitudinal studies to better define the spatial and temporal expansion of the range of the tick and the drivers of this spread.
KW - Cameroon
KW - Genotyping
KW - Phylogenetic tree
KW - Rhipicephalus microplus
KW - Haplotypes
KW - Cross-Sectional Studies
KW - Tick Infestations/epidemiology
KW - RNA, Ribosomal, 16S/genetics
KW - Cameroon/epidemiology
KW - Cattle Diseases/epidemiology
KW - Animal Distribution
KW - Phylogeny
KW - Polymorphism, Genetic
KW - Genetic Variation
KW - Algorithms
KW - Animals
KW - Cattle
KW - Cote d'Ivoire/epidemiology
KW - Epidemiological Monitoring/veterinary
KW - Rhipicephalus/genetics
UR - http://www.scopus.com/inward/record.url?scp=85061244925&partnerID=8YFLogxK
U2 - 10.1016/j.ttbdis.2019.02.002
DO - 10.1016/j.ttbdis.2019.02.002
M3 - Article
C2 - 30765191
AN - SCOPUS:85061244925
SN - 1877-959X
VL - 10
SP - 585
EP - 593
JO - Ticks and Tick-borne Diseases
JF - Ticks and Tick-borne Diseases
IS - 3
ER -