Completing the Puzzle: A Cluster of Hunting Dogs with Tick-Borne Illness from a Fishing Community in Tobago, West Indies.

Eight hunting dogs were visited by a state veterinarian on the island of Tobago, Trinidad and Tobago, West Indies, as owners reported anorexia and paralysis in five of their dogs. The veterinarian observed a combination of clinical signs consistent with tick-borne illness, including fever, anorexia, anaemia, lethargy and paralysis. Blood and ticks were collected from each dog and submitted to a diagnostic laboratory for analysis. Microscopic analysis revealed a mixed infection of intracytoplasmic organisms consistent with Babesia spp. (erythrocyte) and Ehrlichia spp. (monocyte), respectively, from one dog, while a complete blood count indicated a regenerative anaemia (n = 1; 12.5%), non-regenerative anaemia (n = 4; 50%), neutrophilia (n = 3; 37.5%), lymphocytosis (n = 2; 25%), thrombocytopaenia (n = 3; 37.5%) and pancytopaenia (n = 1; 12.5%). DNA isolated from the eight blood samples and 20 ticks (16 Rhipicephalus sanguineus and 4 Amblyomma ovale) were subjected to conventional PCR and next-generation sequencing of the 16S rRNA and 18S rRNA gene for Anaplasma/Ehrlichia and Babesia/Theileria/Hepatozoon, respectively. The DNA of Ehrlichia spp., closely related to Ehrlichia canis, was detected in the blood of three dogs (37.5%), Anaplasma spp., closely related to Anaplasma marginale, in two (25%), Babesia vogeli in one dog (12.5%) and seven ticks (35%) and Hepatozoon canis and Anaplasma spp., in one tick (5%), respectively. These findings highlight the need to test both the vector and host for the presence of tick-borne pathogens when undertaking diagnostic investigations. Further studies are also warranted to elucidate the susceptibility of canids to Anaplasma marginale.

Antimicrobial Resistance in Wildlife in Guadeloupe (French West Indies): Distribution of a Single bla CTX-M-1/IncI1/ST3 Plasmid Among Humans and Wild Animals.

Limited data are available on the contribution of wildlife to the spread of antibacterial resistance. We determined the prevalence of resistance to antibiotics in Escherichia coli isolates collected from wild animals in 2013 and 2014 and the genetic basis for resistance to third-generation cephalosporin in Guadeloupe. We recovered 52 antibiotic-resistant (AR) E. coli strains from 48 of the 884 (5.4%) wild animals tested (46 iguanas, 181 birds, 289 anoles, and 368 rodents at 163 sampling sites). Rodents had higher rates of carriage (n = 38, 10.3%) than reptiles and birds (2.4% and 1.1%, respectively, p < 0.001). A significant association (p < 0.001) was found between the degree of anthropization and the frequency of AR E. coli carriage for all species. The carriage rate of ciprofloxacin- and cefotaxime-resistant isolates was 0.7% (6/884) and 1.5% (13/884), respectively. Most (65.4%) AR E. coli were multi-drug resistant, and the prevalence of extended-spectrum beta-lactamase (ESBL)-producing E. coli was low (n = 7, 0.8%) in all species. Eight ESBL-producing E. coli were recovered, two genetically unrelated isolates being found in one bird. These isolates and 20 human invasive ESBL E. coli isolates collected in Guadeloupe during the same period were investigated by whole genome sequencing. bla CTX-M-1 was the only ESBL gene shared by three animal classes (humans, n = 2; birds, n = 2; rodents, n = 2). The bla CTX-M-1 gene and most of the antimicrobial resistance genes were present in a large conjugative IncI1 plasmid that was highly similar (>99% nucleotide identity) to ESBL-carrying plasmids found in several countries in Europe and in Australia. Although the prevalence of ESBL-producing E. coli isolates was very low in wild animals, it is of concern that the well-conserved IncI1 plasmid-carrying bla CTX-M-1 is widespread and occurs in various E. coli strains from animals and humans.

Identification of a murine cell line that distinguishes virulent from attenuated isolates of the morbillivirus Peste des Petits Ruminants, a promising tool for virulence studies.

Comprehensive pathogenesis studies on Peste des Petits Ruminants virus (PPRV) have been delayed so far by the absence of a small animal model reproducing the disease or an in vitro biological system revealing virulence differences. In this study, a mouse 10T1/2 cell line has been identified as presenting different susceptibility to virulent and attenuated PPRV strains. As evidenced by immunofluorescence test and RT-PCR, both virulent and attenuated PPR viruses penetrated and initiated the replication cycle in 10T1/2 cells, independently of the presence of the SLAM goat receptor. However, only virulent strains successfully completed their replication cycle while the vaccine strains did not. Since 10T1/2 cells are interferon-producing cells, the role of the type I interferon (type I IFN) response on this differentiated replication between virulent and attenuated strains was verified by stimulation or repression. Modulation of the type I IFN response did not improve the replication of the vaccine strains, indicating that other cell factor(s) not yet established may hinder the replication of attenuated PPRV in 10T1/2. This 10T1/2 cell line can be proposed as a new in vitro tool for PPRV-host interaction and virulence studies.

RNA Viruses of Amblyomma variegatum and Rhipicephalus microplus and Cattle Susceptibility in the French Antilles.

Ticks transmit a wide variety of pathogens including bacteria, parasites and viruses. Over the last decade, numerous novel viruses have been described in arthropods, including ticks, and their characterization has provided new insights into RNA virus diversity and evolution. However, little is known about their ability to infect vertebrates. As very few studies have described the diversity of viruses present in ticks from the Caribbean, we implemented an RNA-sequencing approach on Amblyomma variegatum and Rhipicephalus microplus ticks collected from cattle in Guadeloupe and Martinique. Among the viral communities infecting Caribbean ticks, we selected four viruses belonging to the Chuviridae, Phenuiviridae and Flaviviridae families for further characterization and designing antibody screening tests. While viral prevalence in individual tick samples revealed high infection rates, suggesting a high level of exposure of Caribbean cattle to these viruses, no seropositive animals were detected. These results suggest that the Chuviridae- and Phenuiviridae-related viruses identified in the present study are more likely tick endosymbionts, raising the question of the epidemiological significance of their occurrence in ticks, especially regarding their possible impact on tick biology and vector capacity. The characterization of these viruses might open the door to new ways of preventing and controlling tick-borne diseases.

Ticks and Tick-Borne Pathogens of the Caribbean: Current Understanding and Future Directions for More Comprehensive Surveillance.

Ticks are obligate hematophagous arthropods of significant importance to human and veterinary medicine. They transmit a vast array of pathogens, including bacteria, viruses, protozoa, and helminths. Most epidemiological data on ticks and tick-borne pathogens (TBPs) in the West Indies are limited to common livestock pathogens such as Ehrlichia ruminantium, Babesia spp. (i.e., B. bovis and B. bigemina), and Anaplasma marginale, and less information is available on companion animal pathogens. Of note, human tick-borne diseases (TBDs) remain almost completely uncharacterized in the West Indies. Information on TBP presence in wildlife is also missing. Herein, we provide a comprehensive review of the ticks and TBPs affecting human and animal health in the Caribbean, and introduce the challenges associated with understanding TBD epidemiology and implementing successful TBD management in this region. In particular, we stress the need for innovative and versatile surveillance tools using high-throughput pathogen detection (e.g., high-throughput real-time microfluidic PCR). The use of such tools in large epidemiological surveys will likely improve TBD prevention and control programs in the Caribbean.

Diverse gammacoronaviruses detected in wild birds from Madagascar.

To date, infectious bronchitis virus (IBV) is potentially found in wild birds of different species. This work reports the survey of coronaviruses in wild birds from Madagascar based on the targeting of a conserved genome sequence among different groups of CoVs. Phylogenetic analyses revealed the presence of gammacoronaviruses in different species of Gruiformes, Passeriformes, Ciconiiformes, Anseriformes, and Charadriiformes. Furthermore, some sequences were related to various IBV strains. Aquatic and migratory birds may play an important role in the maintenance and spread of coronaviruses in nature, highlighting their possible contribution in the emergence of new coronavirus diseases in wild and domestic birds.