Search tips
Search criteria 


Logo of epidinfectJournal HomepageSubscribeSumbitJournal Homepage
Epidemiol Infect. 1995 October; 115(2): 345–353.
PMCID: PMC2271405

Laboratory reared Amblyomma hebraeum and Amblyomma variegatum ticks differ in their susceptibility to infection with Cowdria ruminantium.


The susceptibility of laboratory reared Zimbabwean Amblyomma hebraeum and A. variegatum ticks to infection with geographically distinct Cowdria ruminantium strains was investigated by feeding both species simultaneously on individual sheep infected with one of the four strains (Crystal Springs [Zimbabwe], Ball 3 [South Africa], Gardel [Guadeloupe] and Nigeria [Nigeria]). A. hebraeum ticks demonstrated a high susceptibility to infection with all four C. ruminantium strains. In comparison, A. variegatum were less susceptible to infection with the Crystal Springs and Ball 3 strains (P < 0.001), but showed a similar susceptibility to the Gardel and Nigeria strains. The differences in susceptibility of A. variegatum to infection with the four strains of C. ruminantium correlated with the origin of these strains. The consistently higher susceptibility of A. hebraeum ticks to infection with geographically different C. ruminantium strains may be one explanation for the observation that heartwater is a more serious problem where A. hebraeum is the vector of the disease.

Full text

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (1.7M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

Images in this article

Click on the image to see a larger version.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Perreau P, Morel PC, Barre N, Durand P. Existence de la cowdriose (heartwater) à Cowdria ruminantium chez les ruminants des Antilles françaises (la Guadeloupe) et des Mascareignes (la Réunion et Ile Maurice). Rev Elev Med Vet Pays Trop. 1980;33(1):21–22. [PubMed]
  • Uilenberg G. Heartwater (Cowdria ruminantium infection): current status. Adv Vet Sci Comp Med. 1983;27:427–480. [PubMed]
  • Bezuidenhout JD. Natural transmission of heartwater. Onderstepoort J Vet Res. 1987 Sep;54(3):349–351. [PubMed]
  • Camus E, Barré N. The role of Amblyomma variegatum in the transmission of heartwater with special reference to Guadeloupe. Ann N Y Acad Sci. 1992 Jun 16;653:33–41. [PubMed]
  • Asselbergs M, Jongejan F, Langa A, Neves L, Afonso S. Antibodies to Cowdria ruminantium in Mozambican goats and cattle detected by immunofluorescence using endothelial cell culture antigen. Trop Anim Health Prod. 1993 Aug;25(3):144–150. [PubMed]
  • Norval RA, Peter T, Meltzer MI. Comparison of the attachment rates of males of the ticks Amblyomma hebraeum and A. variegatum to cattle, sheep and rabbits in the absence of aggregation-attachment pheromone. Exp Appl Acarol. 1992 Sep;15(3):145–152. [PubMed]
  • Camus E, Barré N. Epidemiology of heartwater in Guadeloupe and in the Caribbean. Onderstepoort J Vet Res. 1987 Sep;54(3):419–426. [PubMed]
  • Du Plessis JL. A method for determining the Cowdria ruminantium infection rate of Amblyomma hebraeum: effects in mice injected with tick homogenates. Onderstepoort J Vet Res. 1985 Jun;52(2):55–61. [PubMed]
  • Du Plessis JL, Malan L. Problems with the interpretation of epidemiological data in heartwater: a study on 23 farms. Onderstepoort J Vet Res. 1987 Sep;54(3):427–433. [PubMed]
  • Norval RA, Andrew HR, Yunker CE. Infection rates with Cowdria ruminantium of nymphs and adults of the bont tick Amblyomma hebraeum collected in the field in Zimbabwe. Vet Parasitol. 1990 Jul;36(3-4):277–283. [PubMed]
  • Byrom B, Yunker CE. Improved culture conditions for Cowdria ruminantium (Rickettsiales), the agent of heartwater disease of domestic ruminants. Cytotechnology. 1990 Nov;4(3):285–290. [PubMed]
  • Uilenberg G, Camus E, Barré N. Quelques observations sur une souche de Cowdria ruminantium isolée en Guadeloupe (Antilles françaises). Rev Elev Med Vet Pays Trop. 1985;38(1):34–42. [PubMed]
  • van Winkelhoff AJ, Uilenberg G. Heartwater: cross-immunity studies with strains of Cowdria ruminantium isolated in West and South Africa. Trop Anim Health Prod. 1981 Aug;13(3):160–164. [PubMed]
  • Synge BA. Brain biopsy for the diagnosis of heartwater. Trop Anim Health Prod. 1978 Feb;10(1):45–48. [PubMed]
  • Waghela SD, Rurangirwa FR, Mahan SM, Yunker CE, Crawford TB, Barbet AF, Burridge MJ, McGuire TC. A cloned DNA probe identifies Cowdria ruminantium in Amblyomma variegatum ticks. J Clin Microbiol. 1991 Nov;29(11):2571–2577. [PMC free article] [PubMed]
  • Yunker CE, Mahan SM, Waghela SD, McGuire TC, Rurangirwa FR, Barbet AF, Wassink LA. Detection of Cowdria ruminantium by means of a DNA probe, pCS20 in infected bont ticks, Amblyomma hebraeum, the major vector of heartwater in southern Africa. Epidemiol Infect. 1993 Feb;110(1):95–104. [PMC free article] [PubMed]
  • Mahan SM, Waghela SD, McGuire TC, Rurangirwa FR, Wassink LA, Barbet AF. A cloned DNA probe for Cowdria ruminantium hybridizes with eight heartwater strains and detects infected sheep. J Clin Microbiol. 1992 Apr;30(4):981–986. [PMC free article] [PubMed]
  • Walker JB, Olwage A. The tick vectors of Cowdria ruminantium (Ixodoidea, Ixodidae, genus Amblyomma) and their distribution. Onderstepoort J Vet Res. 1987 Sep;54(3):353–379. [PubMed]
  • Moloo SK. A comparison of susceptibility of two allopatric populations of Glossina pallidipes for stocks of Trypanosoma congolense. Med Vet Entomol. 1993 Oct;7(4):369–372. [PubMed]
  • Eriks IS, Stiller D, Palmer GH. Impact of persistent Anaplasma marginale rickettsemia on tick infection and transmission. J Clin Microbiol. 1993 Aug;31(8):2091–2096. [PMC free article] [PubMed]
  • Byrom B, Yunker CE, Donovan PL, Smith GE. In vitro isolation of Cowdria ruminantium from plasma of infected ruminants. Vet Microbiol. 1991 Feb 1;26(3):263–268. [PubMed]

Articles from Epidemiology and Infection are provided here courtesy of Cambridge University Press