Ehrlichia ruminantium (formerly Cowdria ruminantium). Order Rickettsiales, Family Anaplasmataceae. • Small, Gram negative, pleomorphic coccus, and obligate. caused by the ehrlichial rickettsia Ehrlichia ruminantium (formerly Cowdria ruminantium), heartwater is transmitted from reservoir wildlife hosts (e.g., wildebeest). E. ruminantium is best demonstrated in fixed sections stained with Giemsa. It resembles a Gram-negative coccus, the colour varying from lilac purple.

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Cowdtia serological survey in Mozambique to detect antibodies to Cowdria ruminantiumthe etiologic agent of heartwater, revealed a seroprevalence of 8.

Translocation of 10 serologically negative goats from Tete to farms in the south resulted in two clinical cases of heartwater that were fatal. In addition, four goats seroconverted within the study period of 5 weeks.

One goat showed no symptoms. Two goats died of other causes, whereas the remaining goat went missing after 1 week. Experimental needle infections of goats and sheep were conducted to confirm results and to isolate different strains of C. These data indicate that translocation of goats from the north to the south of Mozambique bears a high risk of C.

Heartwater or cowdriosis is a tick-borne disease affecting domestic ruminants throughout sub-Saharan Africa The disease is caused by Cowdria ruminantiuma rickettsial agent transmitted by ticks of the genus Amblyommaand constitutes a major constraint to livestock development in the affected areas In Mozambique heartwater has been reported to occur throughout the country and mainly during the rainy season 3 Following restocking of animals from the north to the south of the country, the incidence of disease and animal mortality have been extremely high: It is suspected that tick-borne diseases, especially heartwater, contribute to this devastating outcome 7.

To investigate if C. Collected blood samples derived from different geographical areas were tested for the presence of C. These data, which are consistent with a smaller immunofluorescence-based survey 3suggest a considerable difference in exposure to C. The presence of antibodies is likely a good parameter of infection, as small ruminants remain seropositive for several years once they survive a C. The high seroprevalence in the south indicates that animals which are introduced in this area are at high risk of becoming infected with C.

To ascertain that the observed apparent difference in exposure was caused by contact with the agent, 10 serologically negative goats indigenous Landim breed were translocated from Tete province to the Veterinary Faculty in Maputo in southern Mozambique. After a day quarantine period at the Veterinary Faculty in Maputo, the goats were subdivided into two sentinel herds and placed at two farms south of Maputo Porto Henrique and Bom Pastor and were herded together with the local free-ranging goats.


The goats were not treated with any acaricides during the trial. Blood samples were collected on a weekly basis for serological monitoring and at the occurrence of a persistent fever rectal body temperature above Of the five animals that were translocated to Porto Henrique Fig. Examination of Giemsa-stained brain crushed smears from this animal for the presence of rickettsial inclusion bodies in endothelial cells confirmed the presence of C.

At the second farm at Bom Pastor Fig. A second goat seroconverted without obvious clinical symptoms. Map of Mozambique showing the locations where the research was conducted.

Ehrlichia ruminantium

Arrow, translocation of sentinel goats. Inset, enlargement of Maputo province. In order to definitively confirm that C. The entire 16S sequences ruimnantium three samples were determined elsewhere Baseclear, Leiden, The Netherlands.

Ehrlichia ruminantium – Wikipedia

Blastn searches National Center for Biotechnology Information website http: The sequence of a sample from Bom Pastor goat 6 was homologous to Ehrlichia sp.

Since this sample originated from a goat, we believe that it might be Anaplasma oviswhich has been reported to occur in sheep and goats in Mozambique 2.

These data show that C. Nucleotide differences between C. Nucleotide differences between an Anaplasma sp. Blood samples from ruminsntium heartwater cases encountered in the south Bela Vista during the field study were used for experimental infection of Landim goats in Maputo to confirm the presence of C.

Ehrlichia ruminantium

Three goats died shortly after infection, and heartwater could be confirmed. A fourth goat seroconverted after a second inoculation since it was treated with antibiotics 2 days after the first inoculation.

In The Netherlands three seronegative Texelaar sheep were subinoculated with 4 ml of blood no. All three sheep developed fever and were treated with oxytetracyclines. Despite the fact that ruminanitum seroconverted after treatment, no C.

To further investigate if C. After the animal had succumbed, DNA was extracted from the brain of this animal; rickettsial inclusions were detected in the capillary endothelial cells. A hydropericardium was also detected in this animal, clearly indicating a fatal heartwater case.

Ten clones rumonantium sequenced; 4 were homologous to C. Whether the presence of Ehrlichia played a role in the outcome of the disease remains to be investigated. All reacting animals, except sheepwere treated with oxytetracycline at the second day of fever. These data demonstrate that there is a risk of transmission of C. Vaccination prior to translocation and proper tick control might be essential components of a successful restocking program in Mozambique.


The entire 16S sequences of three samples were deposited in GenBank under accession no. Luis Neves and Jos van Putten are thanked for critical reading of the manuscript and helpful comments. National Center for Biotechnology InformationU. Clin Diagn Lab Immunol. Bekker1 Daan Vink2 Carlos M.

Author information Article notes Copyright and License information Disclaimer. This article has been cited by other articles in PMC.

Abstract A serological survey in Mozambique to detect antibodies to Cowdria ruminantiumthe etiologic agent of heartwater, revealed a seroprevalence of 8. Open in a separate window. Isolate b sheep no. Dots, identical nucleotides; dash, gap compared to the sequence of the Senegal isolate. Isolate Nucleotide at position: Nucleotide sequence accession numbers. Vink contributed equally to the work. Different organisms associated with heartwater as shown by analysis of 16S ribosomal RNA gene sequences.

Ticks and tickborne haemoparasites of sheep and goats: Antibodies to Cowdria ruminantium in Mozambican goats and cattle detected by immunofluorescence using endothelial cell culture antigen. Trop Anim Health Prod. Phylogenetic relationship of Cowdria ruminantiumagent of heartwater, to Anaplasma marginale and other members of the order Rickettsiales determined on the basis of 16S rRNA sequence.

Int J Syst Bacteriol. The heterogenicity of Cowdria ruminantium stocks: Onderstepoort J Vet Res. Note on the use of the white mouse for the transport of strains of heartwater. The development of a restocking decision support aid for Mozambique. Department of Agriculture; Validation of the indirect MAP1-B enzyme-linked immunosorbent assay for diagnosis of experimental Cowdria ruminantium infection in small ruminants.

Heartwater Cowdria ruminantium infection: Adv Vet Sci Comp Med. Uilenberg G, Camus E. Woldehiwet Z, Ristic M, editors.

Rickettsial and chlamydial diseases of domestic animals. Phylogenetic position of Cowdria ruminantium Rickettsiales determined by analysis of amplified 16S ribosomal Ruminsntium sequences. Use of a specific immunogenic region on the Cowdria ruminantium MAP1 protein in a serological assay.

Walker J B, Olwage A. The tick vectors of Cowdria ruminantium IxodoideaIxodidae, genus Amblyomma and their distribution. Cultivation of Cowdria ruminantium in bovine vascular endothelial cells. Support Center Support Center. Please review our privacy policy. Died after 10 days of field exposure; heartwater confirmed. Died after 22 days of field exposure; heartwater suspected. Died after 20 days of field exposure with pulmonary distress; heartwater could not be confirmed.