A review of loiasis and its vectors in Gabon.

Loiasis colloquially known as tropical eye worm is a neglected tropical helminthic disease that affects the rural poor population of Gabon. A systematic review of 51 documents (45 peer reviewed papers and six dissertations) over four decades has documented many knowledge gaps on loiasis and its vectors. Higher prevalence and high microfilaremia is typical wherever Chrysops vectors occur. The two main vectors were C. silacea and C. dimidiata along with the savanna species C. longicornis. The two main vectors were only caught around forested national parks at low density (<1 Chrysops per trap per day). Chrysops longicornis was trapped in the savanna zone at higher numbers at a cattle ranch in Nyanga province. Leukoconcentration and Field's stain for L. loa diagnosis performed well as diagnostic tools. However, studies on diagnostic efficacy remain scant, and no study has focused on the evolution of L. loa at the wildlife-human interface of Gabon.

Patterns of foot-and-mouth disease virus detection in environmental samples in an endemic setting.

Foot-and-Mouth Disease virus (FMDV) is endemic in several regions and is a virus that can persist in the environment dependent on pH, relative humidity (RH), temperature, and matrix (i.e., soil, water, or air). Our previously published analysis of available viral persistence data showed that persistence is likely affected by interactions between RH, temperature, and matrix. Understanding these relationships will aid efforts to eliminate FMD, which has significant impacts on economies and food security. In Cameroon, West Africa, the livestock system consists of mobile (transhumant), transboundary trade and sedentary herds. Studying this system can provide information about the patterns of environmental detection of FMDV RNA that may influence approaches to virus elimination on premises during an outbreak. To improve our understanding of these patterns, we collected samples from individuals, vehicles, and along cattle pathways at three sedentary herds beginning on day one of owner-reported outbreaks, ending by day 30, and tested for the presence of FMD viral RNA using rRT-PCR. Our analysis suggests that detection decreases in soil surface samples with increased distance from herd and time from the first report of disease. Whereas time but not distance decreases detection in air samples. Interaction of RH and temperature suggests increased detection at high temperatures (>24°C) and RH (>75%), providing us with new information about the patterns of FMD viral RNA detection in and around cattle herds that could help to inform targeted virus elimination strategies, such as location and application of disinfectants.

A survey of Stomoxys Geoffroy, 1762 (Diptera: Muscidae) in eight administrative regions of Cameroon

ABSTRACT Stomoxys Geoffroy, 1762 are major livestock pests in the tropics and are common in diverse habitats. This study aims to conduct a survey on the Stomoxys fauna of Cameroon. From 2015 to 2017, entomological studies using standard traps (n=204) were conducted in eight administrative regions found in five agro-ecological zones (AEZs) of Cameroon with 606 trap-points over 22,032 traps days. A total of 77,804 Stomoxys specimens were collected, with eight taxa consisting of six species (S. calcitrans (Linnaeus, 1758), S. omega Newstead, Dutton & Todd, 1907, S. xanthomelas Roubaud, 1937, S. inornatus Grunberg, 1906, S. transvittatus Villeneuve, 1916, and S. sitiens (Rondani, 1873)) and two subspecies (Stomoxys niger niger Macquart, 1851 and S. niger bilineatus Grunberg, 1906) identified. Among all the recorded taxa, S. calcitrans and S. n. niger were present in five and seven of the eight regions respectively, but S. sitiens was rare and only found in the North. Furthermore, the highest species number (seven out of eight) was recorded in the Guinee savanna of the Adamawa region. The highest apparent density range of 101 to 200 Stomoxys/ trap/ day (s/t/d) was recorded in the Sudan savanna AEZ of the Far North region. Stomoxys occurred in all the AEZs in eight regions, some of which are major cattle rearing regions. This represents risk for the mechanically transmission of dangerous pathogens in those regions.

Tabanid-transmitted animal trypanosomiasis in Cameroon: Evidence from a study in the tsetse free pastoral zone of Galim.

The role of tabanids as potential transmitters of animal trypanosomiasis (AAT) has not yet been established in Cameroon. The objectives of this study were: (i) to trap and determine the species richness and abundance of tabanids, (ii) to identify circulating trypansomes in cattle and tabanids in a tsetse free area. A three year (2015 to 2017) tabanid survey in six regions of Cameroon was conducted. In Galim village, which is in a tsetse free area, both tabanids and cattle blood samples were screened by PCR for the presence of trypanosome DNA. Tabanids were diverse in Littoral (13 species) and in Adamawa (13 species), but were abundant in the Far North region (36.37 to 145.58 tabanids per trap per day (t/t/d)). In Galim, the tabanid trypanosomal DNA presence was 24.4% (95% CI: 11.25-37.53), while the bovine trypanosomal DNA presence was 4.8% (95% CI: 1.68-11.20). In this village, the Trypanosoma spp. identified in tabanids were T. theileri, T. vivax and T. evansi, while those in cattle were T. theileri and T. vivax. The control of tabanids is required to stop the mechanical spread of AAT in tsetse free areas.

Efficacy and application of a novel topical anaesthetic wound formulation for treating cattle with Foot-and-Mouth disease: A field trial in Cameroon.

Recently, a wound dressing formulation, (Tri-Solfen®, Medical Ethics Pty Ltd, Australia; TS) registered for use in ruminant husbandry in Australia, was registered for Foot-and-Mouth Disease (FMD) therapy in large ruminants in Laos, following clinical observations of improved welfare and healing following treatment of FMD lesions. In November 2019, an FMD outbreak in Cameroon provided an opportunity for a field trial, comparing clinical responses and recoveries to treatments on a sample of cattle (n = 36) comprising three equal groups of animals (n = 12), comparing responses to three treatments: (i) the application to lesions of TS, (ii) the administration of parenteral oxytetraycline commonly used for FMD in Cameroon; and (iii) an untreated control group (C). Appetite scores, lesion healing scores, and changes in dimensions of lesions, were recorded over a 15-day study period. Cattle treated with TS achieved both superior appetite and lesion healing scores with more rapid reduction in dimensions of lesions than other groups. Farmer observations indicated the TS treatment group had a more rapid return to eating with cessation of excessive salivation, and more rapid return of mobility (walking) with absence of overt lameness. The findings indicate that although mortality is usually low in FMD outbreaks, the disease is a debilitating and painful disorder with negative animal welfare impacts that should be addressed. All farmers expressed their desire that the product be made available for use in their region and modelling indicates that TS therapy imposes no additional financial burden on farmers, with the treatment likely to be provided at a similar or reduced cost to current treatment choices. As use of antibiotics for treatment of a viral disease potentially increases pressures for development of antimicrobial resistance and residues in the food chain, TS as an alternative non-antimicrobial therapy should be promoted for wider use in FMD outbreaks.

Risk of Dengue Transmission in Cocody (Abidjan, Ivory Coast).

In recent years, an upsurge of vector-borne diseases has been reported in several parts of the world. Among these is dengue fever, the first arbovirus transmitted by mosquitoes of the genus Aedes. After the detection of the dengue virus serological types (type 1, 2, and 3) in the health district of Cocody-Bingerville in Ivory Coast, entomological investigations were carried out in the city of Cocody (host of most cases) to evaluate the risk of transmission of the disease in view of an effective vector control. Larval prospection together with the pitching of emergence traps was carried out in Caféier 5, Sideci-Coteau, Danga, Ecole de police, Gobelet village, Laurier 9, Lemania, Perles, 7ème tranche, and 12ème arrondissement. Entomological prospections revealed the predominance of Aedes aegypti (97.38%) as the main vector species of dengue viruses in Cocody. The Kruskall-Wallis test showed no statistically significant difference (KW = 1.8, p = 0.407) in the proportions of the vector species collected from the sampled sites. The risk of an outbreak of dengue fever in Cocody and other municipalities in the city of Abidjan is very certain insofar as the larval epidemic risk indices (Habitat Index, HI = 70.9; Container Index, CI = 40.26; and Breteau Index, BI= 21.3) reflect a very high epidemic risk (4 to 9) on the WHO density scale. The occurrence of Aedes aegypti in Cocody indicates the risk of transmission of the Dengue fever virus.