Metrics details. The invasion of West Africa by Rhipicephalus microplus during the past decade has changed the ecological situation of the agent of heartwater Ehrlichia ruminantium in this area. Before, its local vector, Amblyomma variegatum, was the most abundant tick species found on livestock. Today, the abundance of the R. We investigated the potential of this new ecological situation to impact the circulation of E.

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A serological survey in Mozambique to detect antibodies to Cowdria ruminantium , the 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 ruminantium , a rickettsial agent transmitted by ticks of the genus Amblyomma , and 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 , 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 3 , suggest 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. Arrow, translocation of sentinel goats. Inset, enlargement of Maputo province. In order to definitively confirm that C.

The entire 16S sequences of three samples were determined elsewhere Baseclear, Leiden, The Netherlands. 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 ovis , which 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 suspected 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.

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 sheep 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 were 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 sheep , were 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. Bom Pastor. Luis Neves and Jos van Putten are thanked for critical reading of the manuscript and helpful comments.

National Center for Biotechnology Information , U. Clin Diagn Lab Immunol. Cornelis P. Bekker , 1 Daan Vink , 2 Carlos M. Carlos M. Lopes Pereira. Author information Article notes Copyright and License information Disclaimer. Box Phone: 31—30 Fax: 31—30 E-mail: ln. This article has been cited by other articles in PMC.

Abstract A serological survey in Mozambique to detect antibodies to Cowdria ruminantium , the etiologic agent of heartwater, revealed a seroprevalence of 8.

Location No. 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: 69 70 GenBank, A.

Nucleotide sequence accession numbers. Acknowledgments C. Bekker and D. Vink contributed equally to the work. Different organisms associated with heartwater as shown by analysis of 16S ribosomal RNA gene sequences. Vet Parasitol. Ticks and tickborne haemoparasites of sheep and goats: seasonal distribution in Mozambique.

World Anim Rev. 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 ruminantium , agent 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: cross-immunity and serology in sheep and pathogenicity to mice. Onderstepoort J Vet Res.

Haig D A. 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. Reading, United Kingdom: Department of Agriculture; Validation of the indirect MAP1-B enzyme-linked immunosorbent assay for diagnosis of experimental Cowdria ruminantium infection in small ruminants.

Moreira D. Nucleic Acids Res. Uilenberg G. Heartwater Cowdria ruminantium infection : current status. Adv Vet Sci Comp Med. Uilenberg G, Camus E. Rickettsial and chlamydial diseases of domestic animals. Oxford, United Kingdom: Pergamon Press; Phylogenetic position of Cowdria ruminantium Rickettsiales determined by analysis of amplified 16S ribosomal DNA sequences.

Use of a specific immunogenic region on the Cowdria ruminantium MAP1 protein in a serological assay. J Clin Microbiol.


Ehrlichia ruminantium

Heartwater also known as cowdriosis , nintas, and ehrlichiosis is a tick-borne rickettsial disease of domestic and wild ruminants. The disease is spread by bont ticks , which are members of the genus Amblyomma. Affected mammals include cattle , sheep , goats , antelope , and buffalo , but the disease has the biggest economic impact on cattle production in affected areas. The disease's name is derived from the fact that fluid can collect around the heart or in the lungs of infected animals. The disease is common in sub-Saharan Africa and some of the West Indian islands. It was first identified in sheep in South Africa in the s, and had reached the Caribbean by


Animals often acquire the disease when moved on to heartwater infected grazing. It is an intracellular bacteria , residing in endothelial cells and affecting the cardiovascular, respiratory and neurological systems. Cowdriosis has a huge economic impact in Africa, both in direct losses and as an obstruction to the improvement of breeding stock due to the susceptibility of introduced high producing breeds. Cowdriosis is transmitted by bont ticks , mainly of the Amblyomma genus A.


The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report. It resembles a Gram-negative coccus, the colour varying from lilac purple to blue, varying between 0. They most often occur in clumps from 1 or 2 to several thousand in a vacuole in the cytoplasm of endothelial cells. Generally the small and medium-sized organisms occur in large colonies, while the larger ones occur in small colonies. Pleomorphic forms; horseshoe, ring and bacillary shaped, are frequently seen in those colonies that contain very large organisms Pienaar,



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