Diversity of biting midges, mosquitoes and sand flies at four dog shelters in rural and peri-urban areas of Central Morocco

Blood-feeding arthropods are involved in the transmission of several pathogens that have a major impact on public health. Entomological investigations highlighted the composition, abundance, and diversity of flying hematophagous arthropods at four dog shelters located in central Morocco during an eight-month study, with the aim of discussing their vectorial roles and assessing the risk of these shelters as foci for zoonotic diseases. Monitoring of the arthropod fauna for 64 catch nights resulted in the collection of 2,321 biting midges (Ceratopogonidae), 570 mosquitoes (Culicidae), and 475 sand flies (Psychodidae). Fourteen Culicoides species were recorded and dominant species were Culicoides imicola (55.96%), C. paolae (16.07%), C. circumscriptus (10.29%), and C. newsteadi (5.77%). Three mosquito species were collected, including Culex pipiens s.l. (96.84%), Culiseta longiareolata (2.80%), and Cx. perexiguus (0.36%). Ten sand fly species were collected, including seven Phlebotomus species (62.70%) and three Sergentomyia species (37.30%); Sergentomyia minuta was the most dominant species (34.31%), followed by Phlebotomus sergenti (32.42%), typical Ph. perniciosus (8.63%), Ph. alexandri (6.94%), and Ph. riouxi (6.52%). The coexistence of several vectors in these study areas indicates the potential circulation of a wide range of pathogens, including zoonotic ones, thus requiring the implementation of surveillance and control programs to prevent the emergence and spread of disease outbreaks.

A Qualitative Risk Assessment for Bluetongue Disease and African Horse Sickness: The Risk of Entry and Exposure at a UK Zoo

Bluetongue virus (BTV) and African horse sickness virus (AHSV) cause economically important diseases that are currently exotic to the United Kingdom (UK), but have significant potential for introduction and onward transmission. Given the susceptibility of animals kept in zoo collections to vector-borne diseases, a qualitative risk assessment for the introduction of BTV and AHSV to ZSL London Zoo was performed. Risk pathways for each virus were identified and assessed using published literature, animal import data and outputs from epidemiological models. Direct imports of infected animals, as well as wind-borne infected Culicoides, were considered as routes of incursion. The proximity of ongoing disease events in mainland Europe and proven capability of transmission to the UK places ZSL London Zoo at higher risk of BTV release and exposure (estimated as low to medium) than AHSV (estimated as very low to low). The recent long-range expansion of AHSV into Thailand from southern Africa highlights the need for vector competence studies of Palearctic Culicoides for AHSV to assess the risk of transmission in this region.

Bloodmeal analysis in Culicoides midges collected near horses, donkeys and zebras in the Eastern Cape, South Africa

An upsurge in African horse sickness (AHS) in the Eastern Cape, South Africa, from 2006 led to an epidemiological reassessment of the disease there. Light trapping surveys carried out near horses, donkeys and zebras in 2014-2016 collected 39 species of Culicoides midge (Diptera: Ceratopogonidae) that are potential vectors of AHS. To establish if these midges fed on equids, DNA sequences were obtained from the gut contents of 52 female midges (35 freshly blood-fed, 13 gravid and four parous), representing 11 species collected across 11 sites. Culicoides leucostictus fed on all three equids. Culicoides bolitinos, Culicoides imicola and Culicoides magnus fed on both horses and donkeys. Culicoides onderstepoortensis fed on donkeys, and Culicoides similis and Culicoides pycnostictus fed on zebras. Bloodmeals from cows, pigs, warthogs, impalas and a domestic dog were also identified in various species, but none of the midges tested had fed on birds. These results contribute to knowledge of the vectorial capacity of several species of Culicoides with regard to AHS in the Eastern Cape and point to potential reservoir hosts, of which donkeys, zebras and domestic dogs have previously been found to harbour AHS. Blood-fed midges were also obtained throughout winter, indicating the potential for endemic AHS in the province.

Clinical presentation and pathology of suspected vector transmitted African horse sickness in South African domestic dogs from 2006 to 2017

African horse sickness (AHS) is a fatal vector transmitted viral disease of horses caused by the African horse sickness virus (AHSV). This disease is characterised by circulatory and respiratory failure, resulting from vascular endothelial injury affecting many organs. The susceptibility of dogs to AHS has been demonstrated in the past following experimental infection through consumption of infected horse meat. Thirty three clinical cases of AHS in dogs (cAHS) have been documented, without a history of ingesting infected horse meat, over a period of 12 years. The clinical cases included in this study presented with a history of acute respiratory distress syndrome or sudden death. The macroscopic and histological changes were mostly characterised by acute interstitial pneumonia, serofibrinous pleuritis and mediastinal oedema. Confirmation of cAHS was obtained by AHS specific NS4 antibody immunohistochemistry and/or AHSV specific duplex real time RT-quantitative PCR. Here, we document the clinical and postmortem diagnostic features of confirmed cAHS cases with no history of ingestion of AHS infected horse meat.

Blood meal analysis of culicoides (Diptera: ceratopogonidae) in central Tunisia

To evaluate the host preferences of Culicoides species (Diptera: Ceratopogonidae) in Central Tunisia, we identified the source of blood meals of field collected specimens by sequencing of the cytochrome b (cyt b) mitochondrial locus and Prepronociceptine single copy nuclear gene. The study includes the most common and abundant livestock associated species of biting midges in Tunisia: C. imicola, C. jumineri, C. newsteadi, C. paolae, C. cataneii, C. circumscriptus, C. kingi, C. pseudojumineri, C. submaritimus, C. langeroni, C. jumineri var and some unidentified C. species. Analysis of cyt b PCR products from 182 field collected blood-engorged females' midges revealed that 92% of them fed solely on mammalian species, 1.6% on birds, 2.4% on insects and 0.8% on reptiles. The blast results identified the blood origin of biting midges to the species level with exact or nearly exact matches (≥98%). The results confirm the presence of several Culicoides species, including proven vectors in Central Tunisia. Blood meal analyses show that these species will indeed feed on bigger mammals, thereby highlighting the risk that these viruses will be able to spread in Tunisia.