Genetic diversity and population structure of African village dogs based on microsatellite and immunity-related molecular markers.

The village and street dogs represent a unique model of canine populations. In the absence of selective breeding and veterinary care, they are subject mostly to natural selection. Their analyses contribute to understanding general mechanisms governing the genetic diversity, evolution and adaptation. In this study, we analyzed the genetic diversity and population structure of African village dogs living in villages in three different geographical areas in Northern Kenya. Data obtained for neutral microsatellite molecular markers were compared with those computed for potentially non-neutral markers of candidate immunity-related genes. The neutral genetic diversity was similar to other comparable village dog populations studied so far. The overall genetic diversity in microsatellites was higher than the diversity of European pure breeds, but it was similar to the range of diversity observed in a group composed of many European breeds, indicating that the African population has maintained a large proportion of the genetic diversity of the canine species as a whole. Microsatellite marker diversity indicated that the entire population is subdivided into three genetically distinct, although closely related subpopulations. This genetical partitioning corresponded to their geographical separation and the observed gene flow well correlated with the communication patterns among the three localities. In contrast to neutral microsatellites, the genetic diversity in immunity-related candidate SNP markers was similar across all three subpopulations and to the European group. It seems that the genetic structure of this particular population of Kenyan village dogs is mostly determined by geographical and anthropogenic factors influencing the gene flow between various subpopulations rather than by biological factors, such as genetic contribution of original migrating populations and/or the pathogen-mediated selection. On the other hand, the study of oldest surviving dogs suggested a biological mechanism, i.e. a possible advantage of the overal heterozygosity marked by the the microsatellite loci analyzed.

MYD88 and functionally related genes are associated with multiple infections in a model population of Kenyan village dogs.

The purpose of this study was to seek associations between immunity-related molecular markers and endemic infections in a model population of African village dogs from Northern Kenya with no veterinary care and no selective breeding. A population of village dogs from Northern Kenya composed of three sub-populations from three different areas (84, 50 and 55 dogs) was studied. Canine distemper virus (CDV), Hepatozoon canis, Microfilariae (Acantocheilonema dracunculoides, Acantocheilonema reconditum) and Neospora caninum were the pathogens studied. The presence of antibodies (CDV, Neospora), light microscopy (Hepatozoon) and diagnostic PCR (Microfilariae) were the methods used for diagnosing infection. Genes involved in innate immune mechanisms, NOS3, IL6, TLR1, TLR2, TLR4, TLR7, TLR9, LY96, MYD88, and three major histocompatibility genes class II genes were selected as candidates. Single nucleotide polymorphism (SNP) markers were detected by Sanger sequencing, next generation sequencing and PCR-RFLP. The Fisher´s exact test for additive and non-additive models was used for association analyses. Three SNPs within the MYD88 gene and one TLR4 SNP marker were associated with more than one infection. Combined genotypes and further markers identified by next generation sequencing confirmed associations observed for individual genes. The genes associated with infection and their combinations in specific genotypes match well our knowledge on their biological role and on the role of the relevant biological pathways, respectively. Associations with multiple infections observed between the MYD88 and TLR4 genes suggest their involvement in the mechanisms of anti-infectious defenses in dogs.

Altitudinal and seasonal differences of tick communities in dogs from pastoralist tribes of Northern Kenya.

Studies regarding the distribution and ecology of ticks in dogs from Eastern Africa are scarce. Our research was based on a long-term screening of ticks parasitising the domestic dogs living with indigenous people around Lake Turkana, Mt. Kulal and Mt. Nyiru areas, Northern Kenya. A total of 9977 ticks were collected from 1464 dogs of all ages and both sexes. Identification was performed using morphological keys and data were analyzed using the Repeated Measures ANOVA, post-hoc Scheffe test and F test, relating independent variables as seasons and regions. Final results were translated to maps using GIS software. Five species of ticks were identified: Rhipicephalus pulchellus, Rhipicephalus sanguineus sensu lato (s.l.), Rhipicephalus armatus, Amblyomma gemma and Hyalomma truncatum. Our results suggest a statistical difference of the tick community structure related to seasonal and altitudinal distribution. Parasitism with R. armatus and R. pulchellus was higher in September-October than in January, whereas, R. sanguineus s.l. was not influenced by the season. Rhipicephalus armatus was present exclusively on dogs living in semi-desert areas, while R. sanguineus s.l. was the dominant species present on the shores of Lake Turkana. Although R. pulchellus was present in the all studied areas, this species had a significantly higher abundance in the afromontane region of Mt. Kulal and montane xeromorphic forest of Mt. Nyiru; these regions are characterized by elevated humidity and cooler climate. Similar geo-climatic distribution is typical also for A. gemma, which was found in dogs exclusively in Mt. Kulal afromontane area. The current work represents the most extensive study performed on the tick community structure of dogs in Eastern Africa. The results showed a relatively limited tick species diversity, with clear seasonal differences and altitudinal distribution.

Current surveys on the prevalence and distribution of Dirofilaria spp. and Acanthocheilonema reconditum infections in dogs in Romania.

During the last decades, Dirofilaria spp. infection in European dogs has rapidly spread from historically endemic areas towards eastern and northeastern countries, but little or no information is available from these geographical regions. The present study provides a picture of filarial infections in dogs from Romania and compares two tests for the diagnosis of Dirofilaria immitis. From July 2010 to March 2011, blood samples were collected from 390 dogs from nine counties of Romania and serological SNAP tests were performed for the detection of D. immitis antigen. The remaining blood clots were subsequently used for DNA extraction followed by multiplex PCR for assessing filarioid species diversity (i.e. D. immitis, Dirofilaria repens and Acanthocheilonema reconditum). Based on molecular detection, an overall prevalence of 6.92 % (n = 27; 95 % confidence interval (CI) 4.70-10.03 %) for D. repens, 6.15 % (n = 24; 95 % CI 4.07-9.14 %) for D. immitis and 2.05 % (n = 8; 95 % CI 0.96-4.16 %) for A. reconditum was recorded, with significant variations according to sampling areas. Coinfections of D. immitis and D. repens were recorded in 23.91 % (n = 11) positive dogs. A slightly higher prevalence for D. immitis was detected at the SNAP test (n = 28, 7.17 %; 95 % CI 4.91-10.33 %), but this difference was not statistically significant (p = 0.66). However, only 53.57 % (n = 15) of antigen-positive dogs were confirmed by PCR, while other dogs (n = 9) PCR positive for D. immitis were negative at the serology. The present study shows that Dirofilaria species are endemic in the southern and southeastern areas of Romania, This article also provides, for the first time, an epidemiological picture of the distribution of A. reconditum in Romania.

Low rates of antimicrobial-resistant Enterobacteriaceae in wildlife in Taï National Park, Côte d'Ivoire, surrounded by villages with high prevalence of multiresistant ESBL-producing Escherichia coli in people and domestic animals.

Antimicrobial resistance genes can be found in all ecosystems, including those where antibiotic selective pressure has never been exerted. We investigated resistance genes in a collection of faecal samples of wildlife (non-human primates, mice), people and domestic animals (dogs, cats) in Côte d'Ivoire; in the chimpanzee research area of Taï National Park (TNP) and adjacent villages. Single bacteria isolates were collected from antibiotic-containing agar plates and subjected to molecular analysis to detect Enterobacteriaceae isolates with plasmid-mediated genes of extended-spectrum beta-lactamases (ESBLs) and plasmid-mediated quinolone resistance (PMQR). While the prevalence of ESBL-producing E. coli in the villages was 27% in people (n = 77) and 32% in dogs (n = 38), no ESBL-producer was found in wildlife of TNP (n = 75). PMQR genes, mainly represented by qnrS1, were also present in human- and dog-originating isolates from the villages (36% and 42% in people and dogs, respectively), but no qnrS has been found in the park. In TNP, different variants of qnrB were detected in Citrobacter freundii isolates originating non-human primates and mice. In conclusion, ESBL and PMQR genes frequently found in humans and domestic animals in the villages were rather exceptional in wildlife living in the protected area. Although people enter the park, the strict biosecurity levels they are obliged to follow probably impede transmission of bacteria between them and wildlife.

Antimicrobial-resistant Enterobacteriaceae from humans and wildlife in Dzanga-Sangha Protected Area, Central African Republic.

Antimicrobial resistance is a worldwide concern of public health. Unfortunately, resistant bacteria are spreading to all ecosystems, including the strictly protected ones. We investigated antimicrobial resistance in gastrointestinal Enterobacteriaceae of wild mammals and people living within Dzangha-Sangha Protected Areas, Central African Republic, with an emphasis on extended-spectrum ß-lactamase (ESBL) and plasmid-mediated quinolone resistance (PMQR) genes. We compare resistance genes found in microbiota of humans, gorillas habituated and unhabituated to humans and other wildlife. In gorillas, we additionally investigate the presence of ESBL resistant isolates after treatment by ceftiofur. We found a considerable prevalence of multiresistant Enterobacteriaceae isolates with ESBL and PMQR genes in humans (10% and 31%, respectively). Among wildlife the most significant findings were CTX-M-15-producing Klebsiella pneumoniae in a habituated gorilla and a multiresistant Escherichia coli isolate with gene qepA in an unhabituated gorilla. Other isolates from wildlife were mostly represented by qnrB-harboring Citrobacter spp. The relatedness of resistant E. coli was investigated in a PFGE-based dendrogram; isolates from gorillas showed less than 80% similarity to each other and less than 80% similarity to human isolates. No ESBL-producing isolates were found in animals treated by ceftiofur. Although we did not detect any bacterial clone common to wildlife and humans, we detected an intersection in the spectrum of resistance genes found in humans and gorillas, represented by blaCTX-M-15 and qepA.

High prevalence and variability of CTX-M-15-producing and fluoroquinolone-resistant Escherichia coli observed in stray dogs in rural Angola.

Antimicrobial resistance (AMR) represents a serious problem globally, but it is especially pronounced in the tropics, where pressure of infectious diseases is high. We examined resistance in Escherichia coli colonizing gastrointestinal tracts of 17 dogs which have never received antimicrobial treatment, living in central rural Angola. Emphasis was placed on extended-spectrum beta-lactamases (ESBL) and plasmid-mediated quinolone resistance (PMQR). Resistance-carrying plasmids were characterized in size, group of incompatibility and ability to conjugate. Isolates were compared by their pulsed-field gel electrophoresis (PFGE) profiles. Detailed description of 19 E. coli isolates with either ESBL or PMQR genes carried on multiresistant plasmids of different groups of incompatibility indicates that dogs, despite never being treated by antibiotics, are important reservoirs and transmitters of AMR in the study area.

Taming the beast: rabies control in the cradle of mankind.

Between 2006 and 2012, a rabies control programme has been conducted in the area of Lake Turkana in northern Kenya. Spatial data obtained for this project were analysed with the aim of assessing the importance of dog home ranges with the view of possible overlapping between dog populations from adjacent localities. In contrast to our expectation of the maximum home ranges of dogs in the harsh semi-desert environment, the results provided by geographical information system (GIS) analysis showed that in 14 out of 16 localities considered for the study, the dog populations were fully isolated from each other. The data obtained should be helpful for designing rabies control strategies.

Escherichia coli-producing extended-spectrum beta-lactamase CTX-M-15 in a captive South American tapir (Tapirus terrestris).

Only a few reports exist on the occurrence of resistant bacteria in zoo animals. Therefore, an isolation of multiresistant Escherichia coli from the lungs of a captive South American tapir (Tapirus terrestris) lead to its characterization and further investigation of samples from animals inhabiting the same paddock and from the shared environment. The tapir suffered from an intermandibular abscess and pneumonia and was euthanatized after unsuccessful therapy, including administration of antibiotics. The authors performed selective isolation of extended-spectrum beta-lactamase (ESBL)-positive E. coli strains and identification of resistance genes using polymerase chain reaction. Seven multiresistant, ESBL-producing E. coli isolates were obtained, all belonging to the B2 phylogenetic group and showing identical profile on pulsed-field gel electrophoresis. These isolates carried several resistance genes, including the gene bla(CTX-M-15). This case demonstrates the transmission of related epidemiologically important E. coli isolates whose potential transmission to other animals and zoo staff can be assumed.

Dogs of nomadic pastoralists in northern Kenya are reservoirs of plasmid-mediated cephalosporin- and quinolone-resistant Escherichia coli, including pandemic clone B2-O25-ST131.

Resistance in Escherichia coli isolates colonizing gastrointestinal tracts of dogs, cats, and their owners in Northern Kenya was investigated with an emphasis on extended-spectrum beta-lactamases (ESBLs). Totals of 47 (22%, n = 216), 2 (4%, n = 50), and 4 (17%, n = 23) CTX-M-15-producing E. coli isolates were obtained from dogs, cats, and humans, respectively. CTX-M-15-producing E. coli isolates with identical PFGE profiles were detected in animals and humans living in the same area.

Occurrence of filaria in domestic dogs of Samburu pastoralists in Northern Kenya and its associations with canine distemper.

Samples of blood (serum, smears and blood preserved with ethanol) were collected from dogs during a vaccination campaign in northern Kenya in the years 2006 and 2007. Blood was screened for filarial parasites using molecular and microscopy methods and sera were tested for antibodies against canine distemper virus (CDV). Parasitological examination revealed the presence of two species of canine filariae: Acanthocheilonema dracunculoides and A. reconditum. The DNA from the former species was detected in 58% dogs sampled in 2006 and 36% dogs sampled in 2007, whereas the latter was found only in 4.2% samples collected in 2007. Microfilariae were found in 33.8% blood smears collected in 2006 and 10.6% blood smears collected in 2007. The seroprevalence of CDV was 33.4% in 2006 and 11.2% in 2007. The effect of sex, age and CDV-seropositivity/seronegativity on the occurrence of A. dracunculoides was evaluated. Infection by A. dracunculoides was more common in males and in dogs with a positive antibody titer for canine distemper, but evenly distributed among different age groups. The difference in the prevalence of A. dracunculoides in two isolated mountain ranges was not statistically significant. Methodologies available for detection and determination of canine filariae are compared, underlining methodical pitfalls arising through the determination of less common filarial species. The role of single epidemiological factors and possible association between canine distemper and filariasis are discussed.