Showing papers by "Sophie Ravel published in 2016"
TL;DR: Hypoglycaemia was the most notable clinical feature in this case, which was spectacular in its severity and in its refractory nature; glucose administration seemed only to feed the trypanosomes, indicating that treatment of hyp glucosecaemia may in fact have been detrimental.
Abstract: A 20 kg German shepherd dog was presented to a French veterinary teaching hospital for seizures and hyperthermia. The dog had returned 1 month previously from a six-month stay in Senegal and sub-Saharan Africa. Biochemistry and haematology showed severe hypoglycaemia (0.12 g/L), anaemia and thrombocytopenia. Despite administration of large amounts of glucose (30 mL of 30% glucose IV and 10 mL of 70% sucrose by gavage tube hourly), 26 consecutive blood glucose measurements were below 0.25 g/L (except one). Routine cytological examination of blood smears revealed numerous free extracytoplasmic protozoa consistent with Trypanosoma congolense. PCR confirmed a Trypanosoma congolense forest-type infection. Treatment consisted of six injections of pentamidine at 48-hour intervals. Trypanosomes had disappeared from the blood smears four days following the first injection. Clinical improvement was correlated with the normalization of laboratory values. The infection relapsed twice and the dog was treated again; clinical signs and parasites disappeared and the dog was considered cured; however, 6 years after this incident, serological examination by ELISA T. congolense was positive. The status of this dog (infected or non-infected) remains unclear. Hypoglycaemia was the most notable clinical feature in this case. It was spectacular in its severity and in its refractory nature; glucose administration seemed only to feed the trypanosomes, indicating that treatment of hypoglycaemia may in fact have been detrimental.
34 citations
TL;DR: Three Glossina palpalis gambiensis strains were established and are now available for use in future AW-IPM programmes against trypanosomes in West Africa, and the survival of the three strains was dependent on temperature only, and it was unaffected by changing humidity within the tested range.
Abstract: Tsetse flies occur in much of sub-Saharan Africa where they are vectors of trypanosomes that cause human and animal African trypanosomosis. The sterile insect technique (SIT) is currently used to eliminate tsetse fly populations in an area-wide integrated pest management (AW-IPM) context in Senegal and Ethiopia. Three Glossina palpalis gambiensis strains [originating from Burkina Faso (BKF), Senegal (SEN) and an introgressed strain (SENbkf)] were established and are now available for use in future AW-IPM programmes against trypanosomes in West Africa. For each strain, knowledge of the environmental survival thresholds is essential to determine which of these strains is best suited to a particular environment or ecosystem, and can therefore be used effectively in SIT programmes. In this paper, we investigated the survival and fecundity of three G. p. gambiensis strains maintained under various conditions: 25 °C and 40, 50, 60, and 75 % relative humidity (rH), 30 °C and 60 % rH and 35 °C and 60 % rH. The survival of the three strains was dependent on temperature only, and it was unaffected by changing humidity within the tested range. The BKF strain survived temperatures above its optimum better than the SEN strain. The SENbkf showed intermediate resistance to high temperatures. A temperature of about 32 °C was the limit for survival for all strains. A rH ranging from 40 to 76 % had no effect on fecundity at 25–26 °C. We discuss the implications of these results on tsetse SIT-based control programmes.
25 citations
TL;DR: A molecular technique based on the determination of cytochrome oxidase haplotypes of G. gambiensis to discriminate between wild and sterile males is developed and might be useful for other tsetse control campaigns with a SIT component in the framework of the Pan-African Tsetse and Trypanosomosis Eradication Campaign (PATTEC) and, more generally, for other vector or insect pest control programs.
Abstract: The Government of Senegal has embarked since several years on a project that aims to create a tsetse-free area in the Niayes. The project was implemented using an area-wide integrated pest management (AW-IPM) strategy where the sterile flies used for the sterile insect technique (SIT) component were derived from a colony originating from Burkina Faso. Monitoring the efficacy of the sterile male releases requires the discrimination between wild and sterile males that are sampled in monitoring traps. Before being released, sterile males were marked with a fluorescent dye powder. The marking was however not infallible with some sterile flies only slightly marked or some wild flies contaminated with a few dye particles in the monitoring traps, making it difficult to discriminate between wild and sterile males using a UV camera. We developed a molecular technique based on the cytochrome oxidase gene that efficiently discriminates between wild and sterile males. This tool might be useful for other tsetse control campaigns with a SIT component or for other vector or insect pest control programs.
15 citations