Epidemiological Survey on Tick-Borne Pathogens with Zoonotic Potential in Dog Populations of Southern Ethiopia

Clinical Study and Serological Diagnosis of Vector-Borne Pathogens in Sardinian Dogs

Canine vector-borne diseases (CVBDs) comprise a group of infectious diseases caused by a wide range of pathogens transmitted by arthropod vectors. Clinical signs commonly involve symptoms such as fever, anorexia, weight loss, blood disorders, hepatosplenomegaly, and others that can lead to death in dogs with comorbidities. Some pathogens responsible for CVBDs constitute a serious threat to human health due to their zoonotic transmission. This study aimed to determine the prevalence of zoonotic vector-borne diseases (Rickettsia rickettsii, Anaplasma phagocytophilum, Ehrlichia canis, Bartonella henselae, and Leishmania infantum) in domestic Sardinian dogs with and without clinical signs of these pathogens. Blood serum samples were collected from 142 dogs and examined through serological analysis. Clinical signs suggestive of these pathogens were also evaluated. The results obtained showed that 33 (33/140; 23.6%), 22 (22/134; 16.4%), 14 (14/142; 9.9%), 20 (20/66; 30.3%), and 26 (26/108; 24.1%) dogs were seropositive for Rickettsia sp., Anaplasma sp., Ehrlichia sp., Bartonella sp., and Leishmania sp. antibodies, respectively. Among these dogs, 12 dogs presented with at least one clinical sign (8.5%), while 18 (12.7%) showed more than two symptoms at the same time. Furthermore, among the asymptomatic dogs (93/142; 65.5%), 13% (n = 12) tested positive for A. phagocytophilum, 12% (n = 11) tested positive for B. henselae, 9% (n = 8) tested positive for E. canis, 12% (n = 11) tested positive for L. infantum, and 19% (n = 18) tested positive for R. rickettsii. This survey represents the first study assessing different canine vector-borne pathogens in dogs from North Sardinia. Since the pathogens detected here represent emerging zoonotic diseases, these results highlight the need to undertake further studies to increase the knowledge of these under-reported vector-borne pathogens in Sardinia.

Molecular detection of Hepatozoon canis in dogs from Ibagué, Tolima

The genus Hepatozoon consists of apicomplexan protozoans that affect mammals, birds, amphibians, and reptiles. In dogs, the Hepatozoon species include H. canis and H. americanum, which are transmitted by the Rhipicephalus sanguineus tick and cause nonspecific signs, such as fever, weight loss, diarrhea, and blood disorders. These protozoans have a worldwide distribution in Europe, Asia, Africa, and North and South America, including Colombia. The aim of this study was to determine the prevalence and risk factors associated with H. canis in the urban and rural areas of Ibagué, Colombia. Blood samples were collected from 308 dogs (180 rural areas and 128 urban areas). Collected data included dog breed, sex, age, environmental factors, and the presence of ectoparasites. A fragment of the 18S rRNA gene was amplified by PCR for detection of the pathogen and confirmed by sequencing. Among the 308 samples, 14 were positive (14/308, 4.5%) for the presence of H. canis. The partial sequence of the 18S rRNA gene showed identity values >98% with H. canis, forming a cluster with sequences from Latin America. An epidemiological survey found two protective factors: most of the time at home (P=0.055) and overnight stay at home (P=0.03). This is the first molecular study of the prevalence and phylogeny analysis of H. canis in Ibagué, Colombia. The findings may help determine risk factors and enhance our understanding of the geographic distribution of H. canis in Colombia.

Molecular survey of canine tick-borne pathogens in ticks and stray dogs in Dhaka city, Bangladesh

Molecular surveillance of canine tick-borne pathogens (TBPs) in Bangladesh has constantly been undervalued. Therefore, the emergence of new pathogens often remains undetected. This study aimed to screen tick-borne pathogens in stray dogs and ticks in the Dhaka metropolitan area (DMA). Eighty-five dog blood and 53 ticks were collected in six city districts of DMA from September 2022 to January 2023. The ticks were identified by morphology. Screening of TBPs was performed by polymerase chain reaction (PCR), followed by sequencing. The PCR assays were conducted to analyze the 18S rRNA (Babesia gibsoni, B. vogeli, and Hepatozoon canis), 16S rRNA (Anaplasma phagocytophilum, A. platys, and A. bovis), gltA (Ehrlichia canis and Rickettsia spp.), flagellin B (Borrelia spp.) and 16-23S rRNA (Bartonella spp.). Three tick species, Rhipicephalus sanguineus (50/53), R. microplus (1/53), and Haemaphysalis bispinosa (2/53), were identified. Babesia gibsoni (38 out of 85) and A. platys (7 out of 85) were detected in dog blood. In contrast, four pathogens, B. gibsoni (1 out of 53), B. vogeli (1 out of 53), H. canis (22 out of 53), and A. platys (1 out of 53), were detected in the ticks. However, the detection rates of TBPs in dog blood and ticks were not correlated in this study. The phylogenetic analyses suggested that a single genotype for each of the four pathogens is circulating in DMA. This study reports the existence of B. vogeli, H. canis, and A. platys in Bangladesh for the first time.

Tick-borne pathogens Ehrlichia, Hepatozoon, and Babesia co-infection in owned dogs in Central Thailand

Tick-borne pathogens are transmitted by a wide range of tick species and affect both human and animal health. Understanding the diversity of these pathogens and their co-infection rates in domesticated animals in urban areas is crucial for effective disease management and prevention. In this study, a total of 565 owned dogs in the central region of Thailand were investigated for the infection rate of three genera of Ehrlichia, Hepatozoon, and Babesia infection using multiplex PCR. The results revealed an overall infection rate of 19.1%, with Ehrlichia having the highest infection rate (12.2%), followed by Babesia (2.5%) and Hepatozoon (1.4%). The rate of co-infection was 3%, with mixed infections involving two or three genera. Male dogs exhibited a slightly higher infection rate compared to females, although not statistically significant. Young adult dogs (1-3 years) showed the highest infection rate of both single infections and co-infections. Monthly infection rate indicated variations throughout the year, with co-infection rate significantly associated with overall infection rate. Clinical manifestations in three genera of infected dogs included thrombocytopenia and eosinopenia. The results of this study are useful to design strategies for the management and prevention of tick-borne diseases in the study area.

Ehrlichia canis and Rickettsia conorii Infections in Shelter Dogs: Seropositivity and Implications for Public Health

A cross-sectional study was conducted to gain insight into the epidemiology of canine ehrlichiosis and rickettsiosis in northern Portugal. Specific IgG antibodies to Ehrlichia canis were analysed using a commercial enzyme-linked immunosorbent assay (ELISA), and antibodies to Rickettsia conorii were analysed using a commercial indirect immunofluorescence antibody test (IFAT). A total of 113 dogs from two different shelters were sampled, and seroprevalence values of 0.9% (95% confidence (CI): 0.2-4.8%) for E. canis and 9.7 (95% CI: 5.5-16.6%) for R. conorii were found. Multiple logistic regression investigated risk factors for seropositivity. The odds ratios (ORs) of R. conorii seropositivity were higher for female dogs (OR = 6.429; 95% CI: 1.201-34.407). Dogs seropositive for co-infection (E. canis + R. conorii) were more frequently observed among females (OR = 7.606; CI 95%: 1.478-39.132) and in Shelter 2 (OR = 18.229; 95% CI: 2.190-151.756). These findings show that shelter dogs in northern Portugal are exposed to E. canis and R. conorii, which can affect both canines and humans. It is imperative to adopt a One Health approach to educate the public about the hazards of canine zoonoses and develop legislation and procedures to control their spread and preserve public health.

Molecular Survey and Genetic Characteristics of Vector-Borne Pathogens in Domestic Dogs from Four Regions of China

Canine vector-borne diseases are widely distributed around the world. They are transmitted by arthropods, and many seriously threaten the health of animals and humans. In China, our knowledge of Ehrlichia, Hepatozoon, and Mycoplasma species circulating in dogs is still poorly understood. Therefore, the aim of this study was to understand the prevalence and genetic characteristics of canine Ehrlichia spp., Hepatozoon spp., and Mycoplasma spp. in Chongqing (southwest), Fujian (southeast), Shandong (southeast), and Hubei (central) Provinces of China. Blood samples from healthy pet dogs were processed to detect Ehrlichia, Hepatozoon, and Mycoplasma DNA with PCR. Haplotype and phylogenetic analyses were performed on 18S rRNA sequences. Among 306 dogs, no Ehrlichia spp. or Mycoplasma spp. were detected, whereas one Hepatozoon sp. was detected in 10 (3.27%) of the animals. Only Hepatozoon canis was identified and was endemic to Chongqing (2.46%) and Hubei (8.77%). A haplotype analysis identified eight haplotypes among the H. canis isolates. A phylogenetic analysis showed that the H. canis isolates in this study clustered into four clades, together with isolates from different countries and hosts, forming a large group that was clearly separate from other Hepatozoon species. These findings provided new information on the epidemiological characteristics of canine vector-borne diseases in China and will be helpful in the development of efficient measures to safeguard the health and well-being of companion animals and their owners.