Point Seroprevalence Survey ofEhrlichia ruminantiumInfection in Small Ruminants in The Gambia

Abstract

Using the MAP1-B enzyme-linked immunosorbent assay, we tested 1,318 serum samples collected from sheep and goats at 28 sites in the five divisions of The Gambia to determine the Ehrlichia ruminantium seroprevalence rates and to assess the risk for heartwater. About half (51.6%) of 639 sheep were positive, with seroprevalence rates per site varying between 6.9% and 100%. The highest seroprevalence was detected in the western part of the country (88.1% in the Western Division and 62.1% in the Lower River Division). Sheep in the two easterly divisions (Central River and Upper River divisions) showed the lowest seroprevalence of 29.3% and 32.4%, respectively, while those in the North Bank Division showed an intermediate prevalence of 40.6%. In goats, less than one-third (30.3%) of 679 animals tested were positive. The highest seroprevalence was detected in goats in the North Bank Division (59%) and Western Division (44.1%). Goats in the Lower River Division showed an intermediate level of 21.9%, whereas the lowest rates were found in the eastern part of the country (4.8% in the Central River Division and 2.3% in the Upper River Division). At nearly all sites, seroprevalence rates were higher in sheep than in goats. The results show a gradient of increasing heartwater risk for susceptible small ruminants from the east to the west of The Gambia. These findings need to be taken into consideration when future livestock-upgrading programs are implemented.

Ehrlichiosis in Brazil

“…The geographic distribution of some Ehrlichia species has not yet been fully established, although E. canis and E. chaffeensis have been described in most regions of the world (INOKUMA et al, 1999;COCCO et al, 2003;FABURAY et al, 2005;MASTRANDREA et al, 2006;PEREZ et al, 2006;TAMAMOTO et al, 2007;MORO et al, 2009, NDIP et al, 2009. Ehrlichiosis is widely detected across Brazil (Figure 3).…”

Immunisation of sheep against heartwater in The Gambia using inactivated and attenuated Ehrlichia ruminantium vaccines

“…The sheep were maintained tick-free in an insect and tick-proof stable or on tick-proof concrete raised platform under a shed according to the protocol of each experiment with daily cleaning of the housing. In the field trial, exposure to tick challenge was accomplished by allowing animals to graze during the day in the bush in the perimeter and outside the perimeter of ITC, Kerr Seringe, where hearwater is known to occur [5] and at night they were housed in pens.…”

“…The map1 coding sequence of the Kerr Seringe stock, named after the location of origin, was cloned, sequenced and submitted to GenBank and assigned accession no. DQ333230 [5].…”

“…Recent surveys in West Africa indicated the existence in some areas of high levels of heartwater disease risk for susceptible livestock introduced from non-endemic areas [4,5]. The disease can be controlled by a combination of acaricides [6], chemotherapy and immunophylaxis using an infection and treatment method [7].…”

Identification of 19 Polymorphic Major Outer Membrane Protein Genes and Their Immunogenic Peptides inEhrlichia ewingiifor Use in a Serodiagnostic Assay

“…Several members of the genus Ehrlichia have immunodominant surface proteins, e.g., outer membrane protein 1 (OMP-1)/P28s in E. chaffeensis, P30s in E. canis, and Map 1 in Ehrlichia ruminantium, which have been used as serodiagnostic antigens (12,29,32,41,43,51). These surface proteins are encoded by a polymorphic multigene family and are immunologically highly cross-reactive to each other (25, 28-30, 33, 45, 49).…”