Preliminary Study on the Prevalence of Endoparasite Infections and Vector-borne Diseases in Outdoor Dogs in Bulgaria

Vector-borne diseases imported to Poland between 2021 and 2023

Introduction

The aim of the study was to monitor the occurrence of selected vector-borne diseases in anaemic dogs arriving in or returning to Poland from areas endemic for these diseases.

Material and Methods

The study involved 497 dogs, of which 184 came to Poland from Ukraine with their owners fleeing the war. Other animals returned to the country from holidays spent in Croatia (n = 96), Turkey (n = 79), Italy (n = 48), Bulgaria (n = 42), Albania (n = 36) and Romania (n = 12). Molecular biology methods were used for detection of pathogens transmitted by the vectors.

Results

Molecular tests revealed the presence of vector-borne pathogens in 79 dogs. The most commonly diagnosed infection was caused by Babesia canis (27 dogs), followed by infections with Anaplasma phagocytophilum (in 20 dogs), Mycoplasma haemocanis (15 dogs), Bartonella henselae (7 dogs), Ehrlichia canis (4 dogs), Hepatozoon canis (3 dogs), Babesia gibsoni (2 dogs) and Leishmania infantum (1 dog). Most of the sick dogs (n = 39) came from Ukraine. In dogs spending holidays with their owners outside Poland, vector-borne diseases were most often detected after their return from Turkey (n = 16), and next in descending order from Croatia (n = 7), Italy (n = 6), Albania (n = 4), Bulgaria (n = 4) and Romania (n = 3).

Conclusion

The wider migration crisis and increasingly frequent trips of owners with their dogs to areas of endemic infectious and parasitic diseases observed in recent years are the main risk factors for the occurrence of these diseases in Poland. Therefore, constant monitoring of vector-borne diseases, especially in dogs returning from holidays and arriving in Poland from abroad, seems to be crucial for their early detection and introduction of appropriate therapy.

Gastrointestinal Parasites in Owned Dogs in Serbia: Prevalence and Risk Factors

Dogs are the most popular pets worldwide. Close contact between dogs and people increases the risk of transmission of various zoonotic parasitic infections. Given the importance of veterinary medicine in preserving the One Health concept, the aim of this research was to identify intestinal parasites that may have zoonotic potential and to evaluate risk factors (individual and environmental). The research was conducted in Serbia in 2022 and 2023 on 382 owned dogs, using qualitative methods of coprological examination with a concentration on parasitic elements. The overall prevalence of intestinal parasites was 62.6%, with the following detected: protozoa: Cystoisospora spp. (9.2%), Sarcocystis spp. (4.5%), Neospora caninum/Hammondia spp. (3.7%), Giardia intestinalis (11.8%); nematoda: Toxocara canis (11.5%), Toxascaris leonina (4.2%), family Ancylostomatidae (38.0%), Trichuris vulpis (21.5%), Capillaria spp. (10.5%); trematoda: Alaria alata (1.6%) and cestodes from the Taeniidae family (1.3%). Factors like age, size and coat length, as well as the way of living, attitude and diet were linked to a significantly higher (p < 0.05) prevalence of intestinal parasites. Based on the results of coprological diagnostics, this research indicates the importance of educating dog owners, conducting routine parasitological tests on their pets and regular deworming strategies.

Prediction and validation of potential transmission risk of Dirofilaria spp. infection in Serbia and its projection to 2080

Animal and human dirofilariosis is a vector-borne zoonotic disease, being one of the most important diseases in Europe. In Serbia, there are extensive studies reporting the presence of Dirofilaria immitis and D. repens, mainly in the north of the country, where the human population is concentrated and where there is a presence of culicid mosquitoes that transmit the disease. Ecological niche modeling (ENM) has proven to be a very good tool to predict the appearance of parasitosis in very diverse areas, with distant orography and climatologies at a local, continental, and global level. Taking these factors into account, the objective of this study was to develop an environmental model for Serbia that reflects the suitability of the ecological niche for the risk of infection with Dirofilaria spp. with which the predictive power of existing studies is improved. A wide set of variables related to the transmission of the parasite were used. The potential number of generations of D. immitis and the ecological niche modeling method (ENM) were used to estimate the potential distribution of suitable habitats for Culex pipiens. The highest probability of infection risk was located in the north of the country, and the lowest in the southern regions, where there is more orographic relief and less human activity. The model was corroborated with the location of D. immitis-infected dogs, with 89.28% of the country having a high probability of infection. In addition, it was observed that the percentage of territory with optimal habitat for Culex spp. will increase significantly between now and 2080. This new model can be used as a tool in the control and prevention of heartworm disease in Serbia, due to its high predictive power, and will serve to alert veterinary and health personnel of the presence of the disease in the animal and human population, respectively.

Comparative biology of parasitic nematodes in the genus Angiostrongylus and related genera

The rise to prominence of some Angiostrongylus species through associated emerging disease in humans and dogs has stimulated calls for a renewed focus on the biology of this genus and three related genera. Although significant research efforts have been made in recent years these have tended to focus on individual species and specific aspects such as diagnosis and treatment of disease or new records of occurrence and hosts. This comprehensive review takes a comparative approach, seeking commonalities and differences among species and asking such questions as: Which species belong to this and to closely related genera and how are they related? Why do only some species appear to be spreading geographically and what factors might underlie range expansion? Which animal species are involved in the life cycles as definitive, intermediate, paratenic and accidental hosts? How do parasite larvae find, infect and develop within these hosts? What are the consequences of infection for host health? How will climate change affect future spread and global health? Appreciating how species resemble and differ from each other shines a spotlight on knowledge gaps and provides provisional guidance on key species characteristics warranting detailed study. Similarities exist among species, including the basic life cycle and transmission processes, but important details such as host range, climatic requirements, migration patterns within hosts and disease mechanisms differ, with much more information available for A. cantonensis and A. vasorum than for other species. Nonetheless, comparison across Angiostrongylus reveals some common patterns. Historically narrow definitive host ranges are expanding with new knowledge, combining with very broad ranges of intermediate gastropod hosts and vertebrate and invertebrate paratenic and accidental hosts to provide the backdrop to complex interactions among climate, ecology and transmission that remain only partly understood, even for the species of dominant concern. Key outstanding questions concern larval dynamics and the potential for transmission outside trophic relations, relations between infection and disease severity in different hosts, and how global change is altering transmission beyond immediate impacts on development rate in gastropods. The concept of encounter and compatibility filters could help to explain differences in the relative importance of different gastropod species as intermediate hosts and determine the importance of host community composition and related environmental factors to transmission and range. Across the group, it remains unclear what, physiologically, immunologically or taxonomically, delimits definitive, accidental and paratenic hosts. Impacts of infection on definitive host fitness and consequences for population dynamics and transmission remain mostly unexplored across the genus. Continual updating and cross-referencing across species of Angiostrongylus and related genera is important to synthesise rapid advances in understanding of key traits and behaviours, especially in important Angiostrongylus species that are emerging causative agents of disease in humans and other animals.

What Has Happened to Heartworm Disease in Europe in the Last 10 Years?

Heartworm disease caused by Dirofilaria immitis is a vector-borne disease that affects canids and felids, both domestic and wild, throughout the world. It is a chronic disease which causes vascular damage in pulmonary arteries, and in advanced stages, the presence of pulmonary hypertension and right-sided congestive heart failure can be evidenced. Moreover, pulmonary thromboembolism is caused by the death of the worms, which can be lethal for the infected animal. Furthermore, it is the causative agent of human pulmonary dirofilariosis, being a zoonotic disease. The aim of this review was to update the current epidemiological situation of heartworm in Europe in dogs, cats, wild animals, and vectors insects, and to analyse the factors that may have contributed to the continuous spread of the disease in the last decade (2012–2021). In Europe, the disease has extended to eastern countries, being currently endemic in countries where previously only isolated or imported cases were reported. Furthermore, its prevalence has continued to increase in southern countries, traditionally endemic. This distribution trends and changes are influenced by several factors which are discussed in this review, such as the climate changes, presence of vectors in new areas, the appearance of new competent vector species in the continent, increased movement of pets that travelled to or originated from endemic countries, the urbanisation of rural areas leading to the formation of so-called “heat islands”, or the creation of extensive areas of irrigated crops. The continuous expansion of D. immitis must be monitored, and measures adapted to the situation of each country must be carried out for adequate control.

Occurrence of Hookworm and the First Molecular and Morphometric Identification of Uncinaria stenocephala in Dogs in Central Europe

PURPOSE

Hookworms are hematophagous parasitic nematodes that occur in the intestinal tract of various mammals, including humans. The objective of this work was to develop a two-step morphology-molecular analysis-based strategy to identify the genus and the species of eggs and larvae of the Ancylostomatidae family in dogs, which were kept in various living conditions in Slovakia.

METHODS

Faecal samples were collected from 270 dogs kept in two different shelters (160 samples) and in a marginalised Roma community (110 samples). Faecal samples were processed using the flotation method. Microscopically positive faecal samples with hookworm eggs were subjected to a coproculture and the hatched larvae were identified morphometrically, prior to molecular testing. The faecal samples with hookworm´s eggs and individual larvae were identified by a molecular assay based on the amplification of the 18S ribosomal RNA gene fragment. Further, species-specific primer sets were designed for the internal transcribed spacer (ITS 1 region) and the mitochondrial cytochrome c oxidase subunit I (COX1) gene section.

RESULTS

Hookworm eggs were microscopically detected in 9.6% (26/270) of the total number of faecal samples. The prevalence in the Roma settlement was higher, 14.5% (16/110), than in shelters, 6.3% (10/160). Using PCR and subsequent Sanger sequencing, we identified the canine hookworm species Uncinaria stenocephala in all positive samples.

CONCLUSION

Our results have provided new data on the molecular identification of the neglected species U. stenocephala affecting dogs in Slovakia and supplemented the missing information on the prevalence and incidence of hookworms in dogs in Europe.

Deworming Schemes’ Efficacy for Adult Dogs with Mixed Gastro-Intestinal Helminthoses

Mixed gastrointestinal helminthoses, which combines Toxocara canis, Trichuris (T.) vulpis, Toxascaris leoninа, Uncinaria stenocephala, Ancylostoma caninum, and Dipylidium caninum in various combinations, are very common pets’ problems worldwide. It is unlikely necessary to choose between 100 % efficiency and for the patient’s body to heal the infected animals safely. The present work aims to develop an affordable scheme for adult dogs’ deworming, which will create a minimum load on the body due to the low drugs’ toxicity. Mixed breed dogs, 1—5 years old, representing both sexes, spontaneously infected with T. vulpis (100 % prevalence) in combination with other gastrointestinal helminths (from 12.7 to 45.1 %) were selected for study. Regimens combining Caniquantel® Plus (fenbendazole + praziquantel) and fenbendazole with a 24-hour interval were tested. After a single treatment of experimental animals with Caniquantel® Plus, no helminth eggs were detected in their faeces after three days, except for T. vulpis. Seven days after the start of the experiment, the intensity of infection of this nematode decreased by only 22.0 % (P < 0.001). Bodies and fragments of dead helminths were found in faeces 1—4 days after de-worming, with T. vulpis isolated only in 2 days in small quantities (4.54 ± 0.21 specimens per 100 g of faeces). Two-stage deworming with Caniquantel® Plus and fenbendazole after 24 hours resulted in 100 % efficiency against eggs of all parasites after five days. Helminths’ bodies stopped excreting after four days, and T. vulpis was detected within three days in substantive quantities (from 10.03 ± 0.45 to 36.8 ± 1.2 specimens per 100 g of faeces).

Serological evidence of possible Borrelia afzelii lyme disease in Greece

Suggestions that Lyme disease exists in Greece remain controversial and no study to date has definitively identified the presence of a Borrelia species that infects humans. We examined patients throughout Greece suspected for Lyme disease by enzyme-linked immunosorbent assay (ELISA) and by western blotting for Borrelia burgdorferi sensu lato species. We found one patient positive for Borrelia burgdorferi and two patients positive for Borrelia afzelii specific IgG antibodies. Both B. afzelii patients were suffering by neurological manifestations and had never traveled abroad. We provide serological evidence of two autochthonous Lyme disease cases in Greece, possibly caused by B. afzelii.

Simultaneous Exposure to Angiostrongylus vasorum and Vector-Borne Pathogens in Dogs from Italy

Several drivers have recently fostered the expansion of Angiostrongylus vasorum throughout Europe, where Vector-Borne Pathogens (VBPs) are also spreading. However, the level of simultaneous risk of infection is still unknown in canine populations. This study evaluated the simultaneous exposure to A. vasorum and major canine VBPs in dogs of Italy. Sera of 294 dogs were subjected to two ELISAs, detecting A. vasorum circulating antigens and antibodies against the parasite, and to the following assays: (i) SNAP® 4DX (IDEXX Laboratories Inc.) detecting Dirofilaria immitis antigens, and antibodies vs. Borrelia burgdorferi, Anaplasma spp. and Ehrlichia spp. and (ii) IFAT for the detection of antibodies vs. Leishmania infantum, Babesia canis and Rickettsia conorii. Twenty-two (7.5%, CI: 4.8-11.1%) and six (2%, CI: 0.7-4.4%) dogs scored positive for circulating A. vasorum antibodies and antigens, respectively. Seventeen dogs (5.8%, CI: 3.4-9.1%) were positive for A. vasorum antibodies + at least one VBP, three (1%, CI: 0.2-3%) for A. vasorum antigen + at least one VBP, while one dog (0.3%, CI: 0.01-1.88%) was positive for A. vasorum antigen + A. vasorum antibodies + B. canis antibodies. These results show that dogs living in different regions of Italy are at risk of simultaneous infections with both A. vasorum and VBPs. Despite the same scenario being likely in other countries of Europe, the current knowledge is scant. Therefore, further studies are warranted to amplify current epizootiological information and to understand whether control programs should be improved.

Co-infection of Trichuris vulpis and Toxocara canis in different aged dogs: Influence on the haematological indices

Trichuris vulpis and Toxocara canis are worldwide parasitic nematodes affecting dogs and mammals of the Canine family. Due to the special structure of the shells, the eggs of these geohelminths can maintain their viability in soil, sand, water and the environment for a long time. The study involved young (6–12 months old) and adult (1.5–8.0 years old) dogs affected by co-infection of T. vulpis + T. canis; the control group consisted of dewormed healthy animals of the same age. Parasitological examination of dogs' faeces was performed using a "Counting Chamber for Ovoscopic Researches"; morphological parameters, indicators of nutrient metabolism, mineral metabolism and activity of enzymatic systems were determined in blood and serum. According to the results of parasitological research on the dogs, it was found that young animals are more prone to toxocarosis, and adults – trichurosis. The co-infection of nematodes T. vulpis + T. canis in dogs develops several changes in haematological parameters: a significant decrease in erythrocytes, haemoglobin, MCV, MCH, and haematocrit, leukocytosis with basophils and eosinophilia in young infected animals; and eosinophilia and basophilia (15.9 times) in adults, compared with healthy dogs of the same age. Among the changes in serum biochemical parameters, young infected dogs showed a decrease in the concentration of total protein and albumin content, an increase in the content of "acute phase" proteins (α-1, α-2 and β-globulins), an increase in cholesterol and total bilirubin; in adult infected dogs, a decrease in albumin content, an increase in the content of α-1, α-2, and β-globulins, an increase in the concentration of cholesterol and total bilirubin, a decrease in the concentration of urea in comparison with healthy animals were determined. Also, among the indicators of mineral metabolism, a decrease in the concentration of calcium and magnesium in the serum was found in young infected dogs. Among the changes in the enzyme metabolism in the serum of infected dogs, there was an increase in the activity of all studied enzymes in animals of both research groups: ALT, AST, α-amylase, GGT and ALP. Thus, co-infection with nematodes T. vulpis + T. canis has a complex pathogenic effect on the body of dogs of all ages, which manifested itself in multiple changes in haematological parameters. In the future, the authors’ team plan to develop comprehensive measures to combat nematode infections in different living conditions of dogs, taking into account the results of the current research.

A retrospective study of Uncinaria stenocephala in domestic dogs: Age, sex distribution, and risk factors

Background and Aim:

Uncinaria infection often appears in domestic dogs. In the present study, parasitological examination of fecal samples from 782 dogs were analyzed for the presence of Uncinaria stenocephala.

Materials and Methods:

Fecal samples were analyzed by means of a standardized flotation method using a saturated salt solution containing NaNO₃ (specific gravity 1.38), with a centrifugation step.

Results:

The highest prevalence rates were found among young adult dogs (8.3%), followed by puppies (5.4%); the lowest prevalence rates were found in dogs older than 3 years (4.3%). The prevalence was 5.8% among female dogs and 7.2% in male dogs. Coinfections with roundworms and protozoan parasites were frequently observed in U. stenocephala-positive dogs (15%). In total, three types of coinfections were registered. Coinfection of U. stenocephala + Sarcocystids oocysts was recorded in 19.1% of the dogs (n=10). This may relate to higher prevalence of S. oocysts in dogs (n=153; 19.5%). There were two cases of coinfection of U. stenocephala + Toxocara canis (3.9%), which may relate to low prevalence of T. canis (3.9 %). One case of coinfection of Dipylidium caninum+U. stenocephala (0.1%) also appeared.

Conclusion:

The present study showed that male dogs and young dogs were most susceptible to U. stenocephala infection.

First report of fatal autochthonous angiostrongylosis in a dog in Greece

Canine angiostrongylosis caused by Angiostrongylus vasorum is a life-threatening disease which is emerging in regions of Europe. Thus, there is the merit for a continuous epidemiological surveillance in dog populations. This is the first description of a clinical autochthonous case of canine angiostrongylosis in Greece. A 7-month-old, male, mixed-breed dog was presented with progressively worsening anorexia, respiratory distress, coughing, bleeding diathesis and succumbed four days post admission. Gross post mortem examination revealed numerous nodular fistulated lesions in the lungs, and pulmonary cytology and histopathology showed a verminous pyogranulomatous pneumonia. The definitive diagnosis was based on the morphological identification of first stage larvae (L1) retrieved in the feces by the Baermann method, the detection of the circulating antigen by an in-clinic test and the molecular identification of L1. This report underlines the epidemiological and clinical implications, as well as the infection risks when the index of clinical suspicion is low and the disease is unexpected in a country.