Abstract
Ehrlichia ruminantium, the etiologic agent of the economically important disease heartwater, is an obligate intracellular bacterium transmitted by ticks of the genus Amblyomma, particularly A. hebraeum and A. variegatum. Although serologic and microscopic evidence of the presence of heartwater have been reported in ruminants in Cameroon, knowledge of E. ruminantium infection in the tick vector, A. variegatum, is lacking. In order to determine the infectivity of A. variegatum ticks by E. ruminantium, we analysed 500 un-engorged A. variegatum ticks collected by hand-picking from predilection sites from 182 cattle [115 ticks from 82 cattle at Société de Développement et d’Exploitation des Productions Animales (SODEPA) Dumbo ranch (SDR) and 385 ticks from 100 cattle at the Upper Farms ranch (UFR)] by amplification of the open reading frame (ORF) 2 of the pCS20 region of E. ruminantium. PCR amplification of the 279 bp fragment of the pCS20 region detected E. ruminantium DNA in 142 (28.4 %) of the 500 ticks with a higher infection rate (47/115; 40.9 %) observed in ticks from SDR and 24.7 % (95/385) of ticks collected from cattle at UFR. Twenty five randomly selected PCR products were sequenced and results indicated that some of the isolates shared homology with one another and to sequences of E. ruminantium in the GenBank. This report represents the first molecular evidence of E. ruminantium infection in A. variegatum ticks in Cameroon and suggests possible exposure of cattle to this pathogen in our environment.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Allsopp MTEP, Dorfling CM, Maillard JC, Bensaid A, Haydon DT, van Heerden H, Allsopp BA (2001) Ehrlichia ruminantium major antigenic protein gene (map1) variants are not geographically constrained and show no evidence of having evolved under positive selection pressure. J Clin Microbiol 39:4200–4203
Allsopp MT, Van Strijp MF, Faber E, Josemans AI, Allsopp BA (2007) Ehrlichia ruminantium variants which do not cause heartwater found in South Africa. Vet Microbiol 120:158–166
Awa DN (1997) Serological survey of heartwater relative to the distribution of the vector Amblyomma variegatum and other tick species in North Cameroon. Vet Parasitol 68:165–173
Barré N, Garris GI, Borel G, Camus E (1988) Hosts and population dynamics of Amblyomma variegatum (Acari: Ixodidae) on Guadeloupe, French West Indies. J Med Entomol 25(2):111–115
Bekker CPJ, de Vos S, Tanfik A, Sparagano OAE, Jongejan F (2002) Simultaneous detection of Anaplasma and Ehrlichia ruminantium in Amblyomma variegatum ticks by reverse line blot hybridization. Vet Microbiol 89:223–238
Dumler JS, Barbet AF, Bekker CPJ, Dasch GA, Palmer GH, Ray SC, Rikihisa Y, Rurangirwa FR (2001) Reorganisation of genera in the families Rickettsiaceae and Anaplasmataceae in the Order Rickettsiales: unification of some species of Ehrlichia with Anaplasma, Cowdria with Ehrlichia and Ehrlichia with Neorickettsia description of six new species combinations and designation of Ehrlichia equi and “HGE” agent as subjective synonyms of Ehrlichia phagocytophila. Int J Syst Evol Microbiol 51:2145–2165
Faburay B, Geysen D, Munstermann S, Taoufik A, Postigo M, Jongejan F (2007) Molecular detection of Ehrlichia ruminantium infection in Amblyomma variegatum ticks in The Gambia. Exp Appl Acarol 42:6174
Faburay B, Jongejan F, Taoufik A, Ceesay A, Geysen D (2008) Genetic diversity of Ehrlichia ruminantium in Amblyomma variegatum ticks and small ruminants in The Gambia determined by restriction fragment profile analysis. Vet Microbiol 126:189–199
Jordaan JO, Baker JAF (1981) Survival rate on the host and mating capacity of Amblyomma hebreaum (Koch) male ticks. In: Whitehead GB, Gidson JD (eds) Tick biology and control. Tick Research Unit, Rhodes University, Grahamstown, pp 115–117
Martinez D, Vachiery N, Stachurski F, Kandassamy Y, Raliniaina M, Aprelon R, Gueye A (2004) Nested PCR for detection and genotyping of Ehrlichia ruminantium, use in genetic diversity analysis. Ann NY Acad Sci 1026:106–113
Merlin P, Tsangen P, Ronsvoal D (1986) Dynamique saisoniere de l’infestation des bovines par les tiques (Ixodoidea) dans les hauts plateaux de l’Ouest du Cameroun. I. etudes de trois sites autour de Bamenda pendant un an. Rev Elev Med Vet Pays Trop 39:367–376
Merlin P, Tsangen P, Ronsvoal D (1987) Dynamique saisoniere de l’infestation des bovines par les tiques (Ixodoidea) dans les hauts plateaux de l’Ouest du Cameroun. II. Elevage extensif traditionnel. Rev Elev Med Vet Pays Trop 40:133–140
Ndi C, Bayemi PH, Nfi AN, Ekue FN (1998) Preliminary observations on ticks and tick borne diseases in the North West Province of Cameroon II. Bovine heartwater. Rev Elev Med Vet Pays Trop 51:25–28
Ndip LM, Fokam EB, Bouyer DH, Ndip RN, Titanji VPK, Walker DW, McBride JW (2004) Detection of Rickettsia africae in patients and ticks along the Coastal Region of Cameroon. Am J Trop Med Hyg 71:363–366
Perez J-M, Martinez D, Sheikboudou C, Jongejan F, Bensaid A (1998) Characterization of variable immunodorminant antigens of Cowdria ruminantium by ELISA and immunoblots. Parasite Immunol 20:613–622
Peter TF, Perry BD, O’Callaghan CJ, Medley GF, Mlambo G, Barbet AF, Mahan SM (1999) Prevalence of Cowdria ruminantium infection in Amblyomma hebraeum ticks from heartwater endemic areas of Zimbabwe. Epidemiol Infect 123:309–316
Peter TF, Barbet AF, Alleman AR, Simbi BH, Burridge MJ, Mahan M (2000) Detection of the agent of heartwater, Cowdria ruminantium in Amblyomma ticks by PCR: validation and application of the assay to field ticks. J Clin Microbiol 38:1539–1544
Raliniaina M, Meyer DF, Pinarello V, Sheikboudou C, Emboule′ L, Kandassamy Y, Adakal H, Stachurski F, Martinez D, Lefrancois T, Vachiery N (2010) Mining the genetic diversity of Ehrlichia ruminantium using map genes family. Vet Parasitol 167:187–195
Reddy GR, Sulsona CR, Harrison RH, Mahan SM, Burridge MJ, Barbet AF (1996) Sequence heterogeneity of the major antigenic protein 1 genes from Cowdria ruminantium isolates from different geographical areas. Clin Diagn Lab Immunol 3:417–422
Simbi BH, Peter TF, Burridge MJ, Mahan SM (2003) Comparing the detection of exposure to Ehrlichia ruminantium infection on a heartwater endemic farm by pCS20 polymerase chain reaction assay and an indirect MAP-1B enzyme linked immunosorbent assay. Onderstepoort J Vet Res 70:231–235
Stachurski F, Musonge EN, Achu-Kwi MD, Saliki JT (1993) Impact of natural infestation of Amblyomma variegatum on the liveweight gain of male Gudali cattle in Adamawa (Cameroon). Vet Parasitol 49:299–311
Uilenberg G (1983) Heartwater (Cowdria ruminantium infection): current status. Adv Vet Sci Comp Med 27:427–480
Vachiery N, Jeffery H, Pegram R, Aprelon R, Pinarello V, Kandassamy RL, Raliniaina M, Molia S, Savage H, Alexander R, Frebling M, Martinez D, Lefrancois T (2008) Amblyomma variegatum ticks and heartwater on three Caribbean Islands. Ann NY Acad Sci 1149:191–195
Van Heerden H, Steyn HC, Allsopp MTP, Zweygarth E, Josemans AI, Allsopp BA (2004) Characterization of the pCS20 region of different Ehrlichia ruminantium Isolates. Vet Microbiol 101:279–291
Yu XJ, McBride JW, Walker DH (2007) Restriction and expansion of Ehrlichia strain diversity. Vet Parasitol 143:337–346
Acknowledgments
We thank SODEPA staff and Cletus Aghoug for assistance with tick collection. We are grateful to the Laboratory for Emerging Infectious Diseases for the facilities used to carry out this study.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Esemu, S.N., Besong, W.O., Ndip, R.N. et al. Prevalence of Ehrlichia ruminantium in adult Amblyomma variegatum collected from cattle in Cameroon. Exp Appl Acarol 59, 377–387 (2013). https://doi.org/10.1007/s10493-012-9599-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10493-012-9599-9