Potential animal reservoirs (dogs and bats) of human visceral leishmaniasis due to Leishmania infantum in French Guiana.

In French Guiana, cutaneous leishmaniasis is highly endemic, whereas no autochthonous case of visceral leishmaniasis have been reported so far. However, due to its proximity to Brazil which is highly endemic for visceral leishmaniasis, and the high transboundary population flow, an epidemiological challenge could arise at any time. As an overseas department and region and the largest outermost region of the European Union, epidemiological surveillance of visceral leishmaniasis is of great importance. Our study aimed to investigate the presence of Leishmania spp. in domestic (dogs) and sylvatic (bats) animals from French Guiana. Over the 2008-2018 period, samples from 349 animals were collected. They included blood from 179 autochthonous dogs and 59 bats, spleen samples from 33 bats and, blood from 78 military working dogs (MWD) collected before their departure from continental France and at the end of their four-month stay in French Guiana. Samples were screened using real-time polymerase chain reaction (qPCR) assays targeting Leishmania DNA followed by sequencing of 18S rRNA, kDNA and ITS2 genes. L. infantum was detected in 2.3% (8/349) of animals with 1.7% (3/179) of autochthonous dogs, 5.1% (4/78) of MWD returning from French Guiana, whereas they were negative before their departure. One of them dates back to 2012. All these dogs were positive for serological tests. In addition, L. infantum DNA was detectable in one bat spleen sample, belonging to Carollia perspicillata species. We report here for the first time an infection with L. infantum in dogs and bat from French Guiana. Our results suggest the existence of potential reservoir and transmission cycle for visceral leishmaniasis, at least since 2012, which was unknown in this territory until now. Further studies are needed to determine how these animals were infected and which vectors are involved in the transmission in this area.

Seroprevalence survey of equine Lyme borreliosis in France and in sub-Saharan Africa.

A precise assessment of the epidemiological extent of equine Lyme disease is not well established in metropolitan France, French Guiana, and Africa (Chad, Djibouti, Ivory Coast, Gabon, and Democratic Republic of Congo). Blood samples were obtained from 570 horses. The samples were tested for Borrelia burgdorferi infection by a commercial ELISA Dot-Blot method (SNAP 4 Dx; IDEXX S. Laboratory). Lyme disease antibodies were only detected in metropolitan France, specifically in the eastern and center-western regions (48% and 31%). The geographical distribution of the disease follows the distribution of the vector.

Validation of chemoprevention of canine monocytic ehrlichiosis with doxycycline.

Epidemiological (cohort follow-up) and laboratory techniques studies were done to validate a programme of chemoprevention of canine monocytic ehrlichiosis (CME) with this molecule. 614 dogs returning to France after having spent at least 4 months in a CME-endemic area (Africa, Guyana, Middle-East, etc.) were the object of systematic serological testing by indirect immunofluorescence (IFA). The dogs were given 100 mg of doxycycline per os daily for chemoprevention of CME. In addition, HPLC (high performance liquid chromatography) was used to determine plasma levels of doxycycline in 124 of the dogs. The CEM mortality and morbidity rates for the 614 dogs in the chemoprevention programme were nil. The seroconversion rate was 4% (24/614). Seropositive dogs (low titres) were asymptomatic and generally became seronegative after treatment. A study done on 10 dogs shows that doxycyclinaemia was 1.2 (0.94-1.53) microg/ml 2 h after the drug had been administered. After 24 h, the residual concentration was 0.34 (0.26-0.44) microg/ml. Blind doxycyclinaemia tests done on 110 dogs living in Africa (the results for four dogs were nil and therefore eliminated from the study) showed that the minimum observed concentration was always greater than 0.2 microg/ml. Given that, as concerns infection with Ehrlichia spp., the minimum inhibitory concentration of doxycycline is < or = 0.03 microg/ml, dogs receiving chemoprevention treatment should be protected.