Trypanosomiasis challenge estimation using the diminazene aceturate (Berenil) index in Zebu in Gabon.

A longitudinal study was conducted within a cattle ranch in Gabon to determine the diminazene aceturate (Berenil) index (DAI) in a group of Zebu, raised under low tsetse density; this measure providing an assessment of trypanosomiasis risk. The objective was to evaluate the trypanosomiasis pressure thus informing trypanosomiasis control methods and cattle management. Twenty female adult Zebu were monitored for 24 weeks during the dry season. Blood samples were collected on a weekly basis and subjected to parasitological and haematological analysis (n = 480), using the buffy-coat method and the packed cell volume value (PCV), respectively, infected animals were treated with a single intramuscular injection of diminazene aceturate (8 mg/kg). Twenty-nine single infectious events were recorded and a DAI of 1.45 was calculated. Two trypanosome species were identified: Trypanosoma congolense (96.2%) and Trypanosoma vivax (3.8%). The mean PCV value of the infected animals was lower (26.6) compared to non-infected animals (32.0). This study shows that DAI may be a useful tool to assess trypanosomiasis. However, this is a time-consuming method that may be improved by using randomly selected sentinel animals to adapt the chemoprophylactic schemes, hence decreasing the costs and the drug resistance risk.

First demonstration of equid gammaherpesviruses within the gastric mucosal epithelium of horses.

Horses commonly develop gastric mucosal ulcers, similar to humans, a condition known as equine gastric ulcer syndrome (EGUS) that can lead to poor performance and lost training time and care expenses. Unlike humans, however, an infectious bacterial cause of ulcers has not been conclusively identified. Herpesviruses, while well-established causative agents of diseases such as cold sores, genital lesions, and certain types of cancer, have also been implicated in the development of a subset of gastric ulcers in humans. The presence of equid herpesviruses in the gastrointestinal tract and their potential contribution to EGUS has not been evaluated. Here, we provide the first evidence of equid gammaherpesviruses 2 and 5 (EHV-2 and -5) within the epithelium of the gastric mucosa of horses. These viruses were initially detected by a nested PCR screen of gastric tissue samples obtained from client- and university-owned horses with and without ulcers; however, no association with EGUS was found in this limited sample set. We then validated a highly sensitive in situ hybridization (ISH) assay and used this assay to characterize the distribution of these viruses in necropsy gastric tissue samples from five racehorses. Analyses revealed frequent EHV-2 and EHV-5 co-infections within the gastric mucosal epithelium, regardless of the ulcer status. These results are the first to demonstrate the presence of equid gammaherpesviruses in the gastric mucosa of horses and warrants further investigation to determine the contribution of these viruses to the development of EGUS and/or other gastrointestinal diseases.