The potential of Rhipicephalus microplus as a vector of Ehrlichia ruminantium in West Africa.

Heartwater, or cowdriosis, is a virulent tick-borne rickettsial disease of ruminants caused by Ehrlichia ruminantium, biologically transmitted by Amblyomma species (A. variegatum in West Africa). In West Africa, this bacterium was recently reported to naturally infect the invasive cattle tick, Rhipicephalus microplus (Rm) through trans-ovarian transmission from replete adult females to offspring.

Co-circulation of genotypes XIV.2 and XVIII.2 of avian paramyxovirus-1 (Newcastle disease virus) in backyard poultry in Niger.

The causative agent of Newcastle disease (ND) of poultry is the avian paramyxovirus-1, also commonly known as ND virus (NDV). Like in many developing countries, ND is endemic in Niger and has significant economic impact on commercial and backyard poultry production. NDVs were characterized in Niger between 2006 and 2008 and shown to belong to genotypes XIV.

West African Cattle Farmers' Perception of Tick-Borne Diseases.

Worldwide, cattle production is struggling to face the negative impacts caused by ticks and Rhipicephalus (Boophilus) microplus is one of the most harmful ticks for livestock. Most of the people in West Africa depend on cattle farming and subsistence agriculture. The presence of ticks on cattle is a major problem faced by smallholder farmers who fight for their livelihood.

Physico-chemical characterization of dairy gel obtained by a proteolytic extract from Calotropis procera - A comparison with chymosin.

Chymosin is the major enzyme used in cheesemaking but latex enzymes are also used. The aim of this work was to characterize the composition and the structure of dairy gel obtained by an extract of Calotropis procera leaves in comparison with those obtained by chymosin. The biochemical and mineral compositions of the curds and the cheese yields obtained by using Calotropis procera extract or chymosin were relatively similar.

Insecticide and Repellent Mixture Pour-On Protects Cattle against Animal Trypanosomosis.

Background: African animal trypanosomosis (AAT), transmitted by tsetse flies and tick-borne diseases are the main constraints to livestock production in sub-Saharan Africa. Vector control methods such as pour-on offer individual protection against ticks but not against tsetse so far, for which protection has always been communal, through a reduction of their density. The latter requires the treatment of a large part of the herd in a given landscape and is not instantaneous.

Experiences in Tick Control by Acaricide in the Traditional Cattle Sector in Zambia and Burkina Faso: Possible Environmental and Public Health Implications.

Livestock, especially cattle, play a paramount role in agriculture production systems, particularly in poor countries throughout the world. Ticks and tick-borne diseases (TBDs) have an important impact on livestock and agriculture production in sub-Saharan Africa. The authors review the most common methods used for the control of ticks and TBDs.

Ehrlichia ruminantium infects Rhipicephalus microplus in West Africa.

Background: 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.

Community structure, seasonal variations and interactions between native and invasive cattle tick species in Benin and Burkina Faso.

Background: The variation of tick abundance on ruminants had received little attention in West Africa before Rhipicephalus (Boophilus) microplus started to invade this region in the early 2000s. Ten years later, R. microplus was suspected to have replaced the native ticks.

The Recent Evolution of a Maternally-Inherited Endosymbiont of Ticks Led to the Emergence of the Q Fever Pathogen, Coxiella burnetii.

Q fever is a highly infectious disease with a worldwide distribution. Its causative agent, the intracellular bacterium Coxiella burnetii, infects a variety of vertebrate species, including humans. Its evolutionary origin remains almost entirely unknown and uncertainty persists regarding the identity and lifestyle of its ancestors.

Tick control practices in Burkina Faso and acaricide resistance survey in Rhipicephalus (Boophilus) geigyi (Acari: Ixodidae).

Traditional systems account for 95 % of the livestock produced in Burkina Faso. Tick infestation hampers livestock productivity in this area. However, little information exists on tick-control practices used by livestock farmers.

Phylogeography and demographic history of Amblyomma variegatum (Fabricius) (Acari: Ixodidae), the tropical bont tick.

The genetic diversity of Amblyomma variegatum (Fabricius) from four Caribbean islands and five African countries was compared by analyzing the sequences of three gene fragments, two mitochondrial (12SrDNA and D-Loop-DL), and one nuclear (intergenic transcribed spacer 2 [ITS2]). Genetic variability of the ITS2 DNA fragment consisted of only uninformative single nucleotide mutations, and therefore this gene was excluded from further analyses. Mitochondrial gene divergences among African populations and between Caribbean and African populations were very low.

Restricted application of insecticides: a promising tsetse control technique, but what do the farmers think of it?

Background: Restricted application of insecticides to cattle is a cheap and safe farmer-based method to control tsetse. In Western Africa, it is applied using a footbath, mainly to control nagana and the tick Amblyomma variegatum. In Eastern and Southern Africa, it might help controlling the human disease, i.

Clonal origin of emerging populations of Ehrlichia ruminantium in Burkina Faso.

Cowdriosis or heartwater is a major tick-borne disease on ruminants in Africa and the Caribbean. The causative agent is Ehrlichia ruminantium, an intracellular bacterium. Development of vaccines against heartwater has been hampered the limited efficiency of vaccine in the field, thought to be a consequence of the high genetic diversity of strains circulating in a same area.

Efficiency of inactivated vaccines against heartwater in Burkina Faso: impact of Ehrlichia ruminantium genetic diversity.

In order to identify the appropriate strains to use in vaccination trials against heartwater in Burkina Faso, the protective effect of Gardel and Welgevonden strains was assessed against local strains on sheep vaccinated by infection-and-treatment method: Gardel protected significantly against Burkina Faso strains tested (survival rate 59% for immunised sheep vs 13% for control sheep) while Welgevonden did not (survival rate 45% for immunised sheep vs 25% for control sheep). The efficacy of the ISA50 inactivated vaccine, produced under industrial process, was evaluated in sheep during field challenges in two successive years. During year 1, there was a limited protective effect of the Gardel vaccine with 65% of survival rate for the vaccinated group compared to 49% for the control group (N=153, p=0.

Mining the genetic diversity of Ehrlichia ruminantium using map genes family.

Understanding bacterial genetic diversity is crucial to comprehend pathogenesis. Ehrlichia ruminantium (E. ruminantium), a tick-transmitted intracellular bacterial pathogen, causes heartwater disease in ruminants.

MLST scheme of Ehrlichia ruminantium: genomic stasis and recombination in strains from Burkina-Faso.

Heartwater, caused by the intracellular bacterium Ehrlichia ruminantium, is a major tick-borne disease of livestock in Africa also introduced in the Caribbean. The main problem encountered with the control of this disease is the lack of efficient vaccine in the field. This is thought to be related to the high genetic diversity of strains circulating in a same area.

Differential strain-specific diagnosis of the heartwater agent: Ehrlichia ruminantium.

Ehrlichia ruminantium is the causative agent of heartwater, a major tick-borne disease of livestock in Africa introduced in the Caribbean and threatening to emerge and spread in the American mainland. Complete genome sequencing was done for two isolates of E. ruminantium of differing phenotype, isolates Gardel (Erga) from Guadeloupe Island and Welgevonden (Erwe) originating from South Africa and maintained in Guadeloupe.

Understanding the mechanisms of transmission of Ehrlichia ruminantium and its influence on the structure of pathogen populations in the field.

The understanding of the structure of Ehrlichia ruminantium stock population in the field was highlighted by experiments done in controlled conditions on the goat model. The mixture of strains observed in ticks seemed to be due to simultaneous infections rather than successive infections of the carrier. During a dual infection, the timing of Ehrlichia ruminantium circulation of the two stocks in hosts influenced their selection by ticks.