Gastrointestinal Helminths in Horses in Serbia and Various Factors Affecting the Prevalence

PURPOSE

Data on gastrointestinal infections in horses in Southeastern Europe are limited; thus, this study aimed to add to the existing knowledge on this topic by reporting on the prevalence of intestinal parasites of horses in the territory of the Republic of Serbia.

METHODS

In the period from April 2017 to December 2018, parasitological examination of 548 samples from horses of different breed, age and sex from four regions and 18 districts of the country was performed. Coprological diagnostic was done by using qualitative methods without concentration and qualitative methods with concentration of parasitic elements. Quantification of the obtained results was performed using semi-qualitative faecal egg count.

RESULTS

Four helminthoses were detected in the examined samples: P. equorum (8.57%), O. equi (3.65%), strongylid eggs (71.17%) and Anoplocephala spp. (0.91%). The total prevalence of helminthoses was 77.19%. Monoinfections were significantly more present 70.07% compared to coinfections (7.12%). The highest prevalence of helminthoses was detected in free-ranging horses (93.10%-27/29), in autumn 86.67% (117/135) and winter 79.71% (165/207), in Šumadija and West Serbia region (100%), and in the youngest category (100%). Significant difference (p < 0.001) was detected in the prevalence of monoinfections by strongylids and O. equi and also coinfections by strongylid/P. equorum between horses of different age categories.

CONCLUSION

Obtained results are of great contribution to clinical parasitology and pathology, especially from the aspect of animal health, welfare and preservation of horse population.

ZOONOTIC HELMINTHOSIS OF DOMESTIC AND WILD CARNIVORES IN THE EPIZOOTIOLOGIC TERRITORY OF SERBIA

In the last decade, as the result of climate changes, there have been considerable changes in the parasitofauna of domestic and wild carnivores. The prevalence of the existing parasitic species has varied significantly, showing an increasing tendency, and some parasitic species not present before in this epizootiologic territory have been diagnosed as well. It is thought that the reason for such an epizootiological situation is increased presence of owners with their pet animals in the regions endemic for particular zoonotic helminthoses during summer holidays and touristic visits. This tendency has become especially conspicuous in the last several years characterized by warm winters and very hot summers due to global warming effects, with abundant atmospheric precipitation. Oral vaccination of foxes against rabies, regulated in Serbia by appropriate laws since 2010, has led to an increased number of foxes and rise of prevalence of the parasitic diseases for which foxes represent the infection source/reservoir. Continued urbanization of Serbian cities, with the extension of urban belts into the suburbia and recreational (“weekend”) settlements, lead to a closer contact of street dogs and owned dogs with foxes, which results in a significant change in the parasitic fauna of dogs. It is an additional factor, which in the chain fox - street dog - owned dog - human increases the risk and tendency for the occurrence of human infections with zoonotic endoparasites of wild and domestic carnivores. In order to reliably predict the degree of spread of particular zoonotic helminthoses in particular regions in Serbia, for which wild carnivores represent the infection source, it is necessary to institute continued monitoring of the parasitic fauna in this type of wild animals.

Coexistence of genetically different Varroa destructor in Apis mellifera colonies

The aim of this study was to investigate the genetic diversity of Varroa destructor parasitizing Apis mellifera colonies and to test for possible host-parasite association at the mitochondrial DNA (mtDNA) level. Six A. mellifera haplotypes (including a novel C2aa) and five haplotypes of V. destructor were detected in 29 analyzed colonies from eight sampling sites in Serbia. We revealed the presence of the K and S1 haplotypes as well as KS1 and KP1 heteroplasmic mite individuals in all localities, while the P1 haplotype was only found in four sampling sites. Significant differences in V. destructor genetic diversity were found at both apiary and colony levels, with mite haplotypes coexisting in almost all tested colonies. In addition, a significant correlation between the number of analyzed mites per colony and the number of identified V. destructor haplotypes was observed. However, no significant host-parasite relationship was found, suggesting that mites bearing different haplotypes as well as those heteroplasmic individuals are well adapted to the host, A. mellifera, independently of the identified haplotype present in each colony. Our results will contribute to future population and biogeographic studies concerning V. destructor infesting A. mellifera, as well as to better understanding their host-parasite relationship.

Haplotype identification and detection of mitochondrial DNA heteroplasmy in Varroa destructor mites using ARMS and PCR-RFLP methods

In the present study, amplification refractory mutation system (ARMS) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods were used for identification of recently described Serbia 1 (S1) and Peshter 1 (P1) mitochondrial haplotypes of Varroa destructor. Based on single nucleotide polymorphisms (SNPs) within cytochrome oxidase 1 (cox1) and cytochrome b (cytb) gene sequences, a total of 64 adult V. destructor females were analyzed from locations where the S1 and P1 haplotypes had been detected previously. Results of haplotype identification obtained by ARMS and PCR-RFLP methods were completely consistent with the sequencing data. Furthermore, in some analyzed samples the occurrence of site heteroplasmy at haplotype-defining sites was detected, as it was confirmed by double peaks in the sequence chromatograms. Neither mites with simultaneous nucleotide variability, nor those with combined SNP and heteroplasmy in cox1 and cytb were found. Given that this is the first occurrence of site heteroplasmy in V. destructor, the origin of this phenomenon and possible specific traits of heteroplasmic mites have yet to be determined.

First records of Dirofilaria repens in wild canids from the region of Central Balkan

Dirofilaria repens causes an emerging zoonotic disease in Europe, particularly in its southern part, the Mediterranean region. Many reports on human dirofilariosis have been published recently, but little is known about the wildlife hosts and reservoirs of this parasite in nature. This paper presents the first records of adult D. repens specimens from free-ranging carnivores in Central Balkan countries (Serbia and Macedonia). During the period 2009-2013, a total of 145 regularly shot canids were examined for the presence of D. repens adults. In order to investigate their role as hosts and potential wild reservoirs of this zoonosis, 71 wolves (Canis lupus), 48 foxes (Vulpes vulpes) and 26 jackals (Canis aureus) were examined. Under the skin of two wolves (one from Serbia and one from Macedonia) and of a red fox from Serbia D. repens adults were found. In all three cases only one parasite was present. Further research on wild canids is needed, particularly on species widening their range (such as jackals) and those living near human settlements (foxes and jackals), which facilitates the transmission of the parasites to dogs and humans.