A review on the occurrence of companion vector-borne diseases in pet animals in Latin America

Canine vector-borne parasites in the Galapagos

BACKGROUND

The extraordinary Galapagos Islands, with an impressive number of endemic and native species, maintain the interest and curiosity for researchers from all over the world. The native species are known to be vulnerable to new pathogens, cointroduced with their invasive hosts. In the case of invasive parasitic arthropods, their evolutionary success is related to the association with other invasive hosts (such as domestic animals). These associations could become a significant driver of change, as occasionally they can seek another hosts and have the capacity to transmit pathogens between domestic and wild animals. The current study aims to identify the distribution and abundance of canine vector-borne parasites in the Galapagos Islands based on the possibility that some of them could spill over to endemic mammals.

METHODS

A total of 1221 blood samples were randomly collected from privately owned dogs on San Cristóbal, Isabela, Santa Cruz, and Floreana Islands during the years 2021 and 2022. All samples were examined for vector-borne pathogens using the modified Knott's test and conventional, nested, and multiplex polymerase chain reactions (PCRs), followed by sequencing.

RESULTS

The PCR and Knott tests confirmed the presence of Dirofilaria immitis (2%, 25/1221) in all islands. While molecular analyses showed heartworm DNA only in dogs from the San Cristóbal (3.3%) and Isabela (2.4%) Islands. Moreover, other pathogens Babesia vogeli (3%, 37/1221) and Hepatozoon canis (0.2%, 2/1221) were detected for the first time by molecular analyses.

CONCLUSIONS

Dogs from Galapagos are hosts to various pathogens, of which some are potentially zoonotic while some other could be spill-over to endemic endangered carnivores, such as sea lions. To understand and limit their impact, long-term surveillance, control, and awareness is needed.

Ehrlichia canis Vaccine Development: Challenges and Advances

Canine monocytic ehrlichiosis (CME) is an infectious disease caused by Ehrlichia canis, a globally recognized obligate intracellular bacterium. In addition to dogs, other animals, including humans, may be affected. Despite its epidemiological importance and impact on public health, there is currently no commercial vaccine against E. canis. This study aimed to present relevant aspects of the challenges and advances encountered in the development of vaccines for CME and highlight perspectives for future investigations. High genetic variability, along with the various evasion mechanisms employed by E. canis, has hindered the identification of an antigen that targets Th1 cells and is immunogenic to most E. canis isolates, considering their genotypic and phenotypic characteristics. The vaccine must predominantly confer cellular and humoral immunity to achieve robust immune responses. Early production efforts have been challenging due to low immunogenicity, difficulties in establishing long-term protection, and limitations of the techniques used. However, with the refinement of bioinformatic tools, research in this area will be facilitated, thereby accelerating the development of effective vaccines for CME. According to these authors, this vaccine should consist of multiple epitopes.

Metabarcoding using nanopore sequencing enables identification of diverse and zoonotic vector-borne pathogens from neglected regions: A case study investigating dogs from Bhutan

The diversity and prevalence of canine vector-borne pathogens (VBPs) in Bhutan have to date remained unexplored, whilst recent epidemiological surveys in other South Asian nations have found diseases caused by VBPs to be rife in local dog populations. Importantly, many of such VBPs can infect people as well, with a building body of evidence identifying potentially zoonotic rickettsial organisms infecting humans in Bhutan. Given the lack of data on canine pathogens in Bhutan we employed a suite of deep-sequencing metabarcoding methods using Oxford Nanopore Technologies' MinION™ device to holistically characterise the bacterial, apicomplexan and filarial worm blood-borne pathogens of dogs in the country's south. Of the 95 stray, owned and community dogs sampled 78% (95% CI = 69%-85%) were infected with at least one VBP. Pathogen species detected were highly diverse including the bacteria Mycoplasma haemocanis in 16% (95% CI: 10-24%), Ehrlichia canis in 4% (95% CI: 2-10%), Anaplasma platys in 2% (95% CI: 0.5-7%) of dogs as well as the zoonotic species Bartonella clarridgeiae in 1% (95% CI: 0.1-6%), a potentially novel Bartonella spp. and an Ehrlichia chaffeensis-like bacterium, both in 1% (95% CI: 0.1-6%) of dogs. The apicomplexan haemoparasites Hepatozoon canis in 62% (95% CI: 52-71%), Babesia gibsoni in 45% (95% CI: 36-55%) and Babesia vogeli in 3% (95% CI: 1-9%) of dogs were also detected. Finally, 5% (95% CI: 2-12%) of dogs were found to be infected with the filarioid Acanthocheilonema reconditum and 1% (95% CI: 0.1-6%) with zoonotic Dirofilaria sp. hongkongensis. One canine was found positive to the filarioid Setaria tundra, a species normally found infecting cervids. The elucidated diversity of VBP communities highlights the strength of assumption-free diagnostics, such as metabarcoding, in detecting rare, novel, and unexpected pathogens. This approach to identifying pathogen diversity is of critical importance when investigating regions and populations that have thus far been neglected, with the findings aiding the development of future One Health informed strategies for disease control.

Molecular screening of selected vector-borne pathogens circulating in owned dogs in the Caribbean archipelago of Guadeloupe (France)

Vector-borne diseases represent a major health challenge, both because of the complexity of their control, their common zoonotic nature, or the pathology they can cause in the individual. In tropical areas, surveillance of these diseases is even more important, since the activity of vectors is usually continuous throughout the year. To develop effective prophylaxis and surveillance programs, it is important to know the identity and prevalence of these pathogens as well as their distribution in a given territory. In Guadeloupe, a French archipelago located in the Lesser Antilles of the Caribbean, no information exists about vector-borne diseases in companion animals. With this aim, blood samples were obtained from 46 owned dogs with outdoor access from five different veterinary clinics located in the two mainland islands, and the presence of DNA of the main canine vector-borne pathogens (CVBP) was investigated through diverse PCR protocols. At least one pathogen was detected in 30.4 % of the dogs. The most frequently detected CVBP was Coxiella burnetii (17.4 %), followed by Dirofilaria immitis (8.7 %), and Candidatus Mycoplasma haematoparvum, Hepatozoon canis and Rickettsia spp. (2.2 % in all cases). One dog was coinfected with Candidatus M. haematoparvum and D. immitis. All samples were negative for Anaplasma spp., Ehrlichia spp., Bartonella spp., Borrelia burgdorferi sensu lato, piroplasmids, and Leishmania spp. No significant differences in pathogen occurrence were observed between the two main islands or according to the dog's sex and age groups. This study contributes to filling a relevant gap in the knowledge of vector-borne diseases in the Caribbean.

Diversity of Anaplasmataceae Transmitted by Ticks (Ixodidae) and the First Molecular Evidence of Anaplasma phagocytophilum and Candidatus Anaplasma boleense in Paraguay

Anaplasmataceae bacteria are emerging infectious agents transmitted by ticks. The aim of this study was to identify the molecular diversity of this bacterial family in ticks and hosts, both domestic and wild, as well as blood meal sources of free-living ticks in northeastern Paraguay. The bacteria were identified using PCR-HRM, a method optimized for this purpose, while the identification of ticks and their blood meal was performed using conventional PCR. All amplified products were subsequently sequenced. The bacteria detected in the blood hosts included Ehrlichia canis, Anaplasma platys, and Anaplasma phagocytophilum, Candidatus Anaplasma boleense, and Wolbachia spp., which had not been previously reported in the country. Free-living and parasitic ticks on dogs (Canis lupus familiaris) and wild armadillos (Dasypus novemcinctus) were collected and identified as Rhipicephalus sanguineus and Amblyomma spp. The species E. canis, A. platys, A. phagocytophilum, and Ca. A. boleense were detected in domestic dog ticks, and E. canis and A. platys were found for the first time in armadillos and free-living ticks. Blood feeding sources detected in free-living ticks were rodents, humans, armadillos and dogs. Results show a high diversity of tick-borne pathogens circulating among domestic and wild animals in the northeastern region of Paraguay.

Human Babesia odocoilei and Bartonella spp. co-infections in the Americas

BACKGROUND

In recent years, Babesia and Bartonella species co-infections in patients with chronic, nonspecific illnesses have continued to challenge and change the collective medical understanding of "individual pathogen" vector-borne infectious disease dynamics, pathogenesis and epidemiology. The objective of this case series is to provide additional molecular documentation of Babesia odocoilei infection in humans in the Americas and to emphasize the potential for co-infection with a Bartonella species.

METHODS

The development of improved and more sensitive molecular diagnostic techniques, as confirmatory methods to assess active infection, has provided increasing clarity to the healthcare community.

RESULTS

Using a combination of different molecular diagnostic approaches, infection with Babesia odocoilei was confirmed in seven people suffering chronic non-specific symptoms, of whom six were co-infected with one or more Bartonella species.

CONCLUSIONS

We conclude that infection with Babesia odocoilei is more frequent than previously documented and can occur in association with co-infection with Bartonella spp.

Enhancing community health: Veterinary services for underserved areas in Costa Rica with a One Health Approach

In underserved areas of Costa Rica, community veterinary services aim to provide comprehensive care for companion animals, covering preventive, therapeutic, and surgical medicine. Emphasizing a One Health approach, our model focuses on animal welfare, health, and public well-being in vulnerable regions. The project's goal is to ensure the overall well-being of animals, people, and the environment by collaboratively addressing animal health issues and recognizing their interconnected impact on optimal health. Limited resources in underprivileged areas, including restricted access to veterinary care for pets, pose challenges to overall health. Despite its global health benefits, the absence of companion animal veterinary care in these regions has been largely overlooked. Our One Health approach not only addresses animal health but also has a significant impact on human and environmental health, economies, and social factors. This innovative strategy is a pioneering effort to tackle complex health issues in Costa Rica.

Control of companion animal parasites and impact on One Health

The last decades have witnessed an increase in the global population and movements of companion animals, contributing to changes in density and distribution of pet parasites. Control of companion animal parasites (CAPs) becomes increasingly relevant because of the intensifying human-animal bond. Parasites impact on the health of humans and their pets, but also of wildlife and the environment. We conducted a qualitative review on the current advancements, gaps and priorities for the monitoring and treatment of CAPs with a focus on securing public health. There is a need to raise awareness, coordinate global surveillance schemes and better quantify the impact of companion animal parasites on One Health.

Canine leishmaniasis in the Americas: etiology, distribution, and clinical and zoonotic importance

Canine leishmaniasis is a widespread disease on the American continent, with cases reported from Uruguay to the USA and Canada. While numerous Leishmania spp. have been reported in dogs in this region, Leishmania infantum and Leishmania braziliensis are the most common etiological agents of canine leishmaniasis from a continental perspective. Nonetheless, other species may predominate locally in some countries. The participation of dogs in the transmission cycle of various Leishmania spp. has long been speculated, but evidence indicates that their role as reservoirs of species other than L. infantum is negligible. Various native wildlife (e.g., small rodents, marsupials, sloths, and monkeys) are, in fact, the primary hosts of Leishmania spp. in the Americas. In this review, an updated list of Leishmania spp. infecting dogs in the Americas is presented, along with their distribution and clinical and zoonotic importance.

Challenges of animals shelters in caring for dogs infected with Leishmania and other pathogens

The incidence of human Visceral Leishmaniasis (VL) has decreased in Brazil; however, the number of areas reporting human and canine cases has increased, with Leishmania infantum usually preceding human infection. This study aimed to analyze the profile of infectious diseases that are endemic for both human and canine VL, in dogs housed in a shelter located in the state of Rio Grande do Norte, Northeast Brazil. Data was obtained between November/2021 to April/2022. All dogs residing at the shelter (98 dogs) were examined and blood was collected for testing for L. infantum, Ehrlichia canis, and Babesia sp. Statistical analyses considered the clinical and laboratory findings. Of the 98 animals, approximately 43% were positive for L. infantum antibodies, 19% were positive for L. infantum kDNA, and 18% were L. infantum positive by culture. Greater levels of anti-leishmania antibodies were observed in dogs with symptoms suggestive of VL. The dogs tested positive for E. canis (19/98) and B. canis (18/98). Lutzomyia longipalpis was captured inside the shelter, representing 74.25% (n = 225) of whole sandflies in the dog shelter. Concomitant infection by L. infantum and E. canis increased the odds of death. Treatment of VL included the use of allopurinol (n = 48) and miltefosine (n = 8). Treated animals showed more signs of Leishmania infection. Tickborn parasites and Leishmania were prevalent in sheltered dogs in a VL-endemic area, which increases the odds of death and poses an additional challenge for caring for abandoned dogs and at the same time setting protocols to manage reservoirs of L. infantum.

Molecular detection and phylogenetic analysis of Borrelia spp. from sheep and goats blood samples in West Azerbaijan province, Iran

Borrelia species are spirochetes transmitted by ticks that are important in human and animals. In most countries, there is still no molecular epidemiology of borreliosis in ruminants. This study was aimed to evaluate the existence of Borrelia spp. DNA in the blood samples of small ruminants using polymerase chain reaction (PCR) method in West Azerbaijan Province, Iran. To detect Borrelia spp. DNA, about 1,018 ruminants (456 goats and 562 sheep) blood samples were examined from different bioclimatic regions in West Azerbaijan province, Iran. The DNA extracting and PCR were conducted. In sheep, the following prevalence rates were respectively obtained for the 16S rRNA, 5S - 23S rRNA and ospA genes: 3.55% (20/562), 2.13% (12/562) and 0.88% (5/562). And so, the prevalence rates of the genes in goats were 0.87% (4/456) for 5S - 23S rRNA gene, 1.75% (8/456) for 16S rRNA gene and 0.65% (3/456) for ospA gene. The prevalence of Borrelia spp. was significantly different in small ruminants based on the farms and localities. The sheep and goats in humid areas (north of West Azerbaijan) were infected statistically more than those in sub-humid areas (south of West Azerbaijan). It is demonstrated that host species like sheep and goats may have a key role in natural Lyme disease cycles and other borreliosis diseases in Iran.

Prevention of heartworm infection in dogs using a combination of moxidectin, imidacloprid and praziquantel: evidence from a randomized clinical trial

The aim of this study was to evaluate the efficacy of a topical combination of moxidectin 3.5%, imidacloprid 10% and praziquantel 10% for the prevention of Dirofilaria immitis (Leidy, 1856) infection in dogs. For this purpose, a randomized and controlled clinical trial was conducted between August 2021 and October 2022, in the municipality of Goiana, state of Pernambuco, north-eastern Brazil, where heartworm is highly prevalent. Of the 213 dogs initially sampled (baseline), 68 (31.9%) were positive for adult antigens (SNAP 4Dx Plus, Idexx) and/or microfilariae (modified Knott's test). On day 0, 140 negative dogs were randomly included in the treatment and control groups, 70 animals each. During the study, 60 dogs (34 treated and 26 untreated) were removed for different reasons. At the end of the study (day 360 ± 2), 36 treated and 44 untreated were sampled and included in the efficacy calculation. The efficacy against the development of adults and microfilariae was 84.7%, with only one treated dog being positive for adult antigens but negative for microfilariae. On the other hand, eight untreated dogs were positive for adult antigens and/or microfilariae, resulting in a significant difference in the number of positives between groups (Chi-square test = 4.706, df = 1, P = 0.0301). Remarkably, the efficacy against the appearance of D. immitis microfilariae was 100% (i.e., all treated dogs negative) and three untreated dogs were positive for microfilariae. The topical combination of moxidectin 3.5%, imidacloprid 10% and praziquantel 10% significantly reduced the risk of D. immitis infection in treated dogs as compared with untreated dogs, in a highly endemic area in north-eastern Brazil.

First molecular characterization of Dirofilaria Immitis in Cuba

BACKGROUND

Dirofilarioses are widespread diseases caused by mosquito-borne nematodes of the family Onchocercidae, genus Dirofilaria. The major etiologic agent of canine dirofilariosis in the American continent is the zoonotic parasite Dirofilaria immitis. Existing reports of filarioid nematodes in Cuba are based solely on morphological and immunological analysis which do not allow unambiguous identification and/or direct detection of causal agents.

RESULTS

Here we present the molecular characterization of filarioid nematodes found in a dog in Cuba. Based on the molecular and phylogenetic analysis of the 5.8S-ITS2-28S region and cox1 gene fragments, the worms were unambiguously classified as D. immitis. Sequence analysis showed high identity of the gene fragments in this study with others previously obtained from D. immitis found in dogs, wolfs and jackals but also from mosquito vectors of D. immitis.

CONCLUSIONS

Further studies are guarantee to better understand the epidemiological impact of canine dirofilariosis in Cuba as well as the competence of different species of culicid mosquitoes as vectors of Dirofilaria in the country.

Dirofilaria immitis in pet dogs from the metropolitan area of the Colombian Caribbean

A cross-sectional study was carried out to determine the frequency and factors associated with Dirofilaria immitis infection in pet dogs in the metropolitan area of the Colombian Caribbean (northern Colombia). A total of 173 dogs were analyzed by a commercial rapid immunochromatographic test (RIT) and a nested PCR of the cytochrome oxidase subunit I gene, in parallel. Ninety-two (53.2%) of the dogs showed positive results to the RIT, while 59 (34.1%) animals had D. immitis DNA by PCR. Positivity to one or both diagnostic techniques was detected in 104 (60.1%; CI95%: 53.8-67.4) of the sampled dogs. In PCR-positive dogs, phylogenetic analyses evidenced high nucleotide identity (100%) with sequences previously obtained from mosquitoes, dogs and other mammals in different countries. Exercise intolerance (p = 0.002; OR: 2.33; CI95%: 1.37-3.96) and thrombocytopenia (p = < 0.001; OR: 1.95; CI95%: 1.11-3.43) were the main factors associated with D. immitis infection in dogs. The high frequency of D. immitis in dogs indicates a wide distribution of this parasite in the metropolitan area of the Colombian Caribbean, which can be of animal and public health concern. Our results highlight the need to combine different methods to increase the diagnostic accuracy of D. immitis.

Catalysis-Mediated Male Contraception through Black Phosphorus Nanosheets

Nanocontraception has been proposed and received extensive attention in recent years for population control. However, currently developed methods for nanocontraception still face problems in efficacy and safety. Here, we propose catalysis-mediated oxidation as a new strategy for nanocontraception. With the catalytic production of highly oxidative species, male contraception was successfully achieved after the administration of black phosphorus nanosheets into the testes of male mice. Further mechanistic studies revealed that contraception was induced by oxidative stress and apoptosis of spermatogenesis cells. Meanwhile, the apoptosis of germ cells released testis antigen and induced immune cell infiltration, which enhanced reproductive damage. Notably, the introduced black phosphorus nanosheets naturally degraded during the catalytic oxidation process and ultimately converted to harmless phosphates, indicating the safety of the strategy. Furthermore, the catalysis-mediated strategy avoids utilizing additional inducers, such as near-infrared irradiation, magnetic fields, or ultrasound, which may cause severe pain. In summary, the proposed catalysis-mediated contraception can be a self-cleared, convenient, and safe strategy for controlling male fertility.

Canine Babesiosis Caused by Large Babesia Species: Global Prevalence and Risk Factors-A Review

Canine babesiosis is a disease caused by protozoan pathogens belonging to the genus Babesia. Four species of large Babesia cause canine babesiosis (B. canis, B. rossi, B. vogeli, and the informally named B. coco). Although canine babesiosis has a worldwide distribution, different species occur in specific regions: B. rossi in sub-Saharan Africa, B. canis in Europe and Asia, and B. coco in the Eastern Atlantic United States, while B. vogeli occurs in Africa, southern parts of Europe and Asia, northern Australia, southern regions of North America, and in South America. B. vogeli is the most prevalent large Babesia species globally. This results from its wide range of monotropic vector species, the mild or subclinical nature of infections, and likely the longest evolutionary association with dogs. The most important risk factors for infection by large Babesia spp. include living in rural areas, kennels or animal shelters, or regions endemic for the infection, the season of the year (which is associated with increased tick activity), infestation with ticks, and lack of treatment with acaricides.

Sharing of living area and exposure of domestic and wild canids to ticks, Rickettsia parkeri and Rangelia vitalii in the Atlantic Forest of southern Brazil

Spotted fever caused by the bacterium Rickettsia parkeri, and canine rangeliosis caused by the protozoan Rangelia vitalii, are emerging or re-emerging tick-borne diseases in Brazil, where the main tick vectors are Amblyomma ovale and Amblyomma aureolatum, respectively. In the present study, we evaluated exposure to R. parkeri and R. vitalii infection among domestic (Canis lupus familiaris) and wild (Cerdocyon thous) canids sharing living areas within an Atlantic Forest area of southern Brazil. Four different domestic dogs and three different wild canids were captured. Most of the ticks collected from either domestic or wild canids were identified as A. ovale and A. aureolatum. DNA of R. parkeri was amplified from 14% of the A. ovale specimens. Two domestic dogs and two wild canids were seroreactive to R. parkeri antigens with high endpoint titers (>1024). Rangelia vitalii DNA was detected in two wild canids; one of them was resampled 93 days later, again infected by R. vitalii. We report exposure/infection of domestic dogs and wild canids to R. vitalii and/or R. parkeri-infected ticks in an Atlantic Forest area shared by both canid species, indicating that they also shared the same populations of the tick vectors, A. aureolatum and A. ovale. While A. ovale, A. aureolatum, R. parkeri, R. vitalii and C. thous, are all native to the Atlantic Forest, further studies are needed to evaluate the impact of an exotic canine species - C. lupus familiaris - on the enzootic cycles of R. vitalii and R. parkeri, as well as the possible role of domestic dogs in emergence and re-emergence of R. parkeri-spotted fever in humans and canine rangeliosis, respectively.

Canine piroplasmids: Molecular detection and laboratory characterization in dogs from Brasilia, Brazil, with the first molecular evidence of dog exposure to a novel opossum-associated Babesia sp

Canine piroplasmid infections can be caused by Babesia spp., Theileria spp. and Rangelia vitalii. In Brazil, canine babesiosis caused by Babesia vogeli is endemic and reported throughout the country. On the other hand, Rangeliosis caused by R. vitalii has only been described so far in the South and Southeast regions. Despite that, studies analyzing the laboratory and molecular characterization of these hemoprotozoa are still scarce. To investigate the occurrence, the laboratory features, the molecular characterization, and the diversity of piroplasmids from Midwestern Brazil, a survey was performed using blood samples obtained from 276 domestic dogs from Brasília, Federal District, Midwestern Brazil. A broad-range quantitative PCR (qPCR) targeting the mitochondrial large subunit ribosomal DNA (LSU4) was used to detect piroplasmid DNA. The overall molecular occurrence of piroplasmids was 11.2% (31/276), with 9.7% (27/276) of the sequences identified as Babesia vogeli (98-100% identity to B. vogeli isolate from the USA). Based on a partial 18S rRNA sequence pairwise alignment (-250 bp), 1.4% (4/276) of the sequences showed only 76.8% identity with B. vogeli but 100% identity with opossum-associated Babesia sp. (MW290046-53). These findings suggest the exposure of dogs from Brazil to a recently described Babesia sp. isolated from white-eared opossum. None of the analyzed dogs was positive for Theileria spp. or R. vitalii. Subsequently, all positive sequences were submitted to three additional PCR assays based on the 18S rRNA, cox-1, and cytb genes, aiming at performing a haplotype network analysis. Haplotype network using cox-1 sequences showed the presence of six different haplotypes of B. vogeli; one of them was shared with isolates from Brazil, the USA, and India. When including animals co-infected with other vector-borne diseases, piroplasmid-positive dogs had 2.3 times higher chance of having thrombocytopenia than the negative ones. The molecular results demonstrated that the compared Babesia vogeli sequences showed a low variability as well as evidence of exposure to a putative novel opossum-associated Babesia sp. in dogs from Midwestern Brazil.

Tick-associated diseases identified from hunting dogs during the COVID-19 pandemic in a Mayan community in Yucatan, Mexico

Background

Hunting activity in the Mayan communities has increased due to COVID-19 and domestic dogs have gained more importance. Due to their proximity to humans, domestic dogs are a bridge between tick-borne diseases (TBDs) and humans and their peri-domestic environment. In Mexico, and especially in rural regions, there were not adequate records of TBDs during the SARS-CoV-2 pandemic.

Aim

Identify TBD of ticks collected during the COVID-19 pandemic in a rural community.

Methods

Tick capture was carried out in March 2021, in Teabo, Yucatan. Ticks were removed using from domestic dogs and placed in ethanol. Collected ticks were morphologically identified and underwent DNA extraction and a partial segment of the mitochondrial 16S-rDNA gene was amplified to corroborate the tick species. The DNA was screened for the presence of Anaplasma spp., Borrelia spp., Ehrlichia spp., and Rickettsia spp. Purified amplification products were submitted for sequencing and the results were compared to those deposited in GenBank using BLAST.

Results

We collected 33 ectoparasites, Ixodes affinis, Rhipicephalus sanguineus, Rhipicephalus microplus, and Amblyomma mixtum on 11 hunting dogs. The most frequent ectoparasite was R. sanguineus (66%). We detected the presence of DNA of Rickettsia endosymbiont in I. affinis and Anaplasma platys in R. sanguineus. Rickettsia endosymbiont presented a similarity of 100% with the partial sequence of R. endosymbiont of I. affinis isolate IACACTM001 16S ribosomal RNA gene and the sequence of A. platys had a similarity of 100% with the partial sequence of the isolate 23-33TX 16S ribosomal RNA gene of A. platys from dogs from Texas, USA and with the partial sequence of the isolate L134 16S ribosomal RNA gene of Ehrlichia canis from dogs from Piura, Peru.

Conclusion

We confirmed for the first time the presence of A. platys in R. sanguineus and R. endosymbiont in I. affinis ticks from dogs in the state of Yucatan.

Acute Phase Proteins in Dogs with Natural Infection by Trypanosoma cruzi

Acute phase proteins have been used as tools for the diagnosis, monitoring, and prognosis of several diseases in domestic animals. However, the dynamics of these proteins in infection by Trypanosoma cruzi, the causative agent of Chagas disease in dogs, is still unknown. The aim of this study was to determine concentrations of acute phase proteins (C-reactive protein, haptoglobin, ferritin and paraoxonase-1) in dogs in a coastal town of Ecuador, with natural Trypanosoma cruzi infection with or without seroreactivity of Ehrlichia canis, Ehrlichia ewingii, Anaplasma phagocytophilum, Anaplasma platys, Borrelia burgdorferi and Dirofilaria immitis. For the detection of Trypanosoma cruzi serum antibodies, two different antigen-based enzyme-linked immunosorbent assay tests were implemented. For the detection of seroreactivity of Ehrlichia canis, Ehrlichia ewingii, Anaplasma phagocytophilum, Anaplasma platys, Borrelia burgdorferi and Dirofilaria immitis, an IDEXX SNAP^® 4Dx^® test was used. To determine the concentration of C-reactive protein and ferritin, an immunoturbidimetric assay was used; haptoglobin concentration was measured using a commercial colorimetric method validated in dogs; a spectrophotometric method was used to determine the serum concentration of paraoxonase-1. Results showed a reduction in the serum levels of paraoxonase-1 in Trypanosoma cruzi-seroreactive dogs, either with or without seroreactivity to other vector-borne diseases. A serum ferritin increment was observed in Trypanosoma cruzi-seroreactive dogs with seroreactivity to any other vector-borne diseases. Our findings suggest that paraoxonase-1 levels are reduced in Trypanosoma cruzi-seroreactive dogs without evident clinical signs of Chagas disease, despite their seroreactivity to the other vector-borne diseases studied. These findings could indicate an oxidative stress response in Trypanosoma cruzi-seroreactive dogs with no evident signs of inflammation.

Molecular detection of vector-borne pathogens in cats tested for FIV and FeLV

The aim of this study was to detect molecularly vector borne pathogens (VBPs) in domiciled cats tested for Feline immunodeficiency virus (FIV) and Feline leukemia virus (FeLV). Blood samples (n = 119) were analyzed microscopically and molecularly through PCR and sequenced for the detection of the following pathogens: piroplasmids., Bartonella henselae, Cytauxzoon felis, Ehrlichia canis, Leishmania spp., hemotropic Mycoplasma spp., Trypanosoma spp., and Ricketssia spp. Animals were also serological assessed for detection of antibodies against FIV and FeLV. Out of all animals, 20.16% (24/119) tested positive for at least one VBPs at molecular examination. Conversely, no animal resulted positive at microscopic analysis. The most prevalent pathogen was hemotropic Mycoplasma haemofelis (8.40%; 10/119), followed by Candidatus Mycoplasma haemominutum (5.88%; 7/119), E. canis (5.04%; 6/119), C. felis (0.84%; 1/119) and B. henselae (0.84%; 1/119). One animal (0.84%; 1/119) was co-infected with. E. canis and B. henselae. A total of 5.88% (7/119) and 1.68% (2/119) tested positive for FIV and FeLV, respectively. Data of this study demonstrate that owned cats can be at risk of hemotropic Mycoplasma spp., E. canis, C. felis and B. henselae. Therefore, preventive measures against vectors of these pathogens should be implemented in order to reduce the risk of exposition and consequently infection. Additionally, aggressive behaviors among cats should be avoided, especially because hemotropic Mycoplasma spp. may be transmitted through the bite of animals.

Heartworm adulticide treatment: a tropical perspective

Dirofilaria immitis (the canine heartworm) is widespread in the tropics, with prevalence surpassing 30% in high-risk areas. In addition to the suitable climatic conditions that favour mosquito abundance and filarial larva development, there is low compliance with the recommended year-round use of preventives in these transmission hotspots. This represents a major concern, considering that melarsomine (first-line heartworm adulticide) is unavailable in several tropical countries, resulting in the so-called slow-kill protocol being the only available adulticide treatment option. In this article, the members of TroCCAP (Tropical Council for Companion Animal Parasites) review the current distribution of heartworm in the tropics and the availability of melarsomine, and discuss alternatives for the management of heartworm infections in dogs.

Suppurative spinal meningomyelitis in a dog with intra-neutrophilic cerebrospinal fluid cells Ehrlichia canis morulae

A 2-year-old castrated male Creole Shepherd mixed dog was presented for non-ambulatory paraparesis of the pelvic limbs. The magnetic resonance imaging and cerebrospinal fluid (CSF) analysis were consistent with meningomyelitis. Positive serology for Ehrlichia canis/Ehrlichia ewingii suggested exposure to a pathogen; qPCR on the serum and the CSF confirmed active infection. Ehrlichial morulae were observed within CSF and peripheral blood polymorphonuclear neutrophils; a species-specific PCR confirmed E. canis infection. This is an interesting report of E. canis infection in a dog with morulae observed in neutrophils both in the peripheral blood and CSF.

Analysis of genetic diversity and population structure of Babesia gibsoni

Babesia gibsoni is a tick-borne apicomplexan protozoan causing canine babesiosis. This parasite has diploid sexual reproduction in ticks, during which genetic exchanges can occur leading to increased genetic diversity, which is an important factor in adapting to environmental changes. Exploring the genetic variation of B. gibsoni population can provide a foundation for understanding the patterns of disease transmission and developing babesiosis control strategies. Partial 18S rRNA fragment sequences were obtained from 11 B. gibsoni isolates collected from different regions in China and 117 publicly available sequences were from 12 geographical areas including China. The genetic variation, demographic expansion and population structure were examined. A total of 34 haplotypes were identified among B. gibsoni populations. Analysis of molecular variance, pairwise Fst and structure analysis showed that high genetic variation within populations, low genetic differentiation and obvious mixture haplotype were apparent in a single continent, but higher genetic differentiation was detected across different continents. Neutrality tests implied that B. gibsoni populations had experienced population extension. These findings will contribute to understand the genetics and evolution of B. gibsoni and will be useful for formulating effective management strategies to prevent and control this parasite.

First Report of Acanthocheilonema reconditum Outbreak in Canines with Clinical Signs of Anemia from Southwestern Colombia

Different nematodes affect canines, however Acanthocheilonema reconditum was considered mostly a non-pathogenic parasite. Climate change, animal migration, and other factors transformed the dynamics of vector-borne diseases, including filariasis. Since 2016, a sudden increase in the number of dogs with microfilaremia was reported by different veterinary centers in Cali, southwest Colombia. The objective of this study was to molecularly identify the etiologic agent of this filariasis outbreak detected in this city, using PCR−RFLP and evaluating dogs’ clinical signs. From 2018−2019, canine filariasis cases were prospectively evaluated after a microscopic test, recruiting 82 cases and 43 healthy controls from 2971 samples. Acanthocheilonema reconditum (Nematoda, Onchocercidae) was identified in 61.3% of the cases (49/82) by PCR−RFLP. Sanger sequencing of the 5.8S ribosomal RNA gene and internal transcribed spacer-2 fragment was additionally performed on seven cases, confirming A. reconditum in all of them. The filariasis cases are statistically associated with male dogs who have clinical signs of anemia, low levels of hemoglobin and hematocrit (p < 0.0001), and high levels of plasma proteins (p < 0.001). This emerging canine disease constitutes an important public health concern among veterinarians and active surveillance is advised to explore its zoonotic potential.

Molecular detection of vector-borne pathogens in semen from dogs in southeastern Brazil

Vector-borne pathogens (VBPs) are primarily transmitted by arthropod vectors, but secondary ways of transmission have been described, including via venereal route. Nonetheless, there is still limited research on possible sexual transmission of VBPs in dogs. We molecularly investigated the presence of vector-borne pathogens in semen from dogs living in an area where these agents are endemic. Upon PCR testing, seven out of 22 (31.8%) semen samples tested positive for at least one VBP, whereas simultaneous positivity to two or more pathogens was detected in three (13.6%) dogs. Among pathogens detected in semen, Trypanosoma cruzi (n = 1) and Leishmania infantum (n = 3) were identified to species level by restriction fragment length polymorphism analysis. Attempts to sequence PCR products from other pathogens were unsuccessful, but coupled epidemiological and molecular data suggest the presence of Anaplasma platys (n = 5), Babesia vogeli (n = 1) and Ehrlichia canis (n = 1) in semen from dogs. Further experimental studies would be needed to confirm the sexual transmission hypothesis for these VBPs and also the possible implications of these findings for canine reproduction.

Technological advances in the serological diagnosis of Chagas disease in dogs and cats: a systematic review

Background

Chagas disease (CD) is caused by Trypanosoma cruzi, which is transmitted mainly through the feces/urine of infected triatomine bugs. The acute phase lasts 2–3 months and is characterized by high parasitemia and nonspecific symptoms, whereas the lifelong chronic phase features symptoms affecting the heart and/or digestive tract occurring in 30–40% of infected individuals. As in humans, cardiac abnormalities are observed in T. cruzi-infected dogs and cats. We reviewed the technological advances in the serological diagnosis of CD in dogs and cats.

Methods

A review of the published literature during the last 54 years (1968–2022) on the epidemiology, clinical features, diagnosis, treatment and prevention of CD in dogs and cats was conducted.

Results

Using predefined eligibility criteria for a search of the published literature, we retrieved and screened 436 publications. Of these, 84 original studies were considered for inclusion in this review. Dogs and cats are considered as sentinels, potentially indicating an active T. cruzi transmission and thus the risk for human infection. Although dogs and cats are reputed to be important for maintaining the T. cruzi domestic transmission cycle, there are no commercial tests to detect past or active infections in these animals. Most published research on CD in dogs and cats have used in-house serological tests prepared with native and/or full-length recombinant antigens, resulting in variable diagnostic performance. In recent years, chimeric antigens have been used to improve the diagnosis of chronic CD in humans with encouraging results. Some of them have high performance values (> 95%) and extremely low cross-reactivity rates for Leishmania spp., especially the antigens IBMP-8.1 to IBMP-8.4. The diagnostic performance of IBMP antigens was also investigated in dogs, showing high diagnostic performance with negligible cross-reactivity with anti-Leishmania infantum antibodies.

Conclusions

The development of a commercial immunodiagnostic tool to identify past or active T. cruzi infections in dogs and cats is urgently needed. The use of chimeric recombinant T. cruzi antigens may help to fill this gap and is discussed in this review.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05476-4.

Vector-borne pathogens of zoonotic concern in dogs from a Quilombola community in northeastern Brazil

Canine vector-borne pathogens (CVBPs) comprise a group of disease agents mainly transmitted by ticks, fleas, mosquitoes and sand flies. In this study, we assessed the presence of CVBPs in an Afro-descendent community (Quilombola) of northeastern, Brazil. Dog blood samples (n = 201) were collected and analyzed by rapid test for the detection of antibodies against Leishmania spp., Anaplasma spp., Ehrlichia spp. and Borrelia burgdorferi sensu lato (s.l.), and antigens of Dirofilaria immitis. In addition, polymerase chain reactions were performed for Anaplasmataceae, Babesia spp., Hepatozoon spp., Rickettsia spp. and B. burgdorferi s.l. Overall, 66.7% of the dogs scored positive to at least one pathogen at serological and/or molecular methods. Antibodies against Ehrlichia spp. were the most frequently detected (57.2%; n = 115/201), followed by Anaplasma spp. (8.5%; n = 17/201), Leishmania spp. (8.5%; n = 17/201) and B. burgdorferi s.l. (0.5%; n = 1/201). For D. immitis, 11 out of 201 (5.5%) animals scored positive. At the molecular analysis, 10.4% (n = 21/201) of the samples scored positive for Babesia spp./Hepatozoon spp., followed by Anaplasmataceae (5.0%; n = 10/201) and Rickettsia spp. (3.0%; n = 6/201). All samples were negative for B. burgdorferi s.l. Our data demonstrated the presence of CVBPs in the studied population, with a high seropositivity for Ehrlichia spp. In addition, considering the detection of zoonotic pathogens in dogs and their relationship with people from Quilombola communities, effective control strategies are advocated for minimizing the risk of infection in this socially vulnerable human population and their pets.

Ticks (Acari: Ixodidae) and Associated Pathoge Collected From Domestic Animals and Vegetation in Stann Creek District, Southeastern Belize, Central America

Data on the prevalence and distribution of ticks and tick-borne diseases in Belize are lacking. Ticks (n = 564) collected from dogs, horses, and vegetation in two villages in Stann Creek District in southeastern Belize in 2018, were molecularly identified and screened for tick-borne nonviral human pathogens. The identity of 417 ticks was molecularly confirmed by DNA barcoding as Rhipicephalus sanguineus (Latreille) (66.43%), Amblyomma ovale Koch (15.59%), Dermacentor nitens Neumann (11.51%), Amblyomma sp. ADB0528 (3.6%), and the remainder being small records (2.87%) of Amblyomma coelebs Neumann, Amblyomma imitator Kohls, Amblyomma tapirellum Dunn, Amblyomma auricularium Conil, and Amblyomma maculatum Koch. Individual tick extracts were screened for the presence of Rickettsia spp., Babesia spp., Babesia microti, Borrelia spp., Ehrlichia spp., and Anaplasma spp. using available conventional polymerase chain reaction (PCR) assays. Rickettsia parkeri strain Atlantic Rainforest was identified in five specimens of A. ovale, and one other unidentified tick, all collected from dogs. Another unidentified tick-also collected from a dog-tested positive for an undefined but previously detected Ehrlichia sp. With the exception of D. nitens, all eight other tick species identified in this study were collected on dogs, suggesting that dogs could be usefully employed as sentinel animals for tick surveillance in Belize.

Recent Advances in the Immunologic Method Applied to Tick-Borne Diseases in Brazil

Zoonotic-origin infectious diseases are one of the major concerns of human and veterinary health systems. Ticks, as vectors of several zoonotic diseases, are ranked second only to mosquitoes as vectors. Many ticks’ transmitted infections are still endemic in the Americas, Europe, and Africa and represent approximately 17% of their infectious diseases population. Although our scientific capacity to identify and diagnose diseases is increasing, it remains a challenge in the case of tick-borne conditions. For example, in 2017, 160 cases of the Brazilian Spotted Fever (BSF, a tick-borne illness) were confirmed, alarming the notifiable diseases information system. Conversely, Brazilian borreliosis and ehrlichiosis do not require notification. Still, an increasing number of cases in humans and dogs have been reported in southeast and northeastern Brazil. Immunological methods applied to human and dog tick-borne diseases (TBD) show low sensitivity and specificity, cross-reactions, and false IgM positivity. Thus, the diagnosis and management of TBD are hampered by the personal tools and indirect markers used. Therefore, specific and rapid methods urgently need to be developed to diagnose the various types of tick-borne bacterial diseases. This review presents a brief historical perspective on the evolution of serological assays and recent advances in diagnostic tests for TBD (ehrlichiosis, BSF, and borreliosis) in humans and dogs, mainly applied in Brazil. Additionally, this review covers the emerging technologies available in diagnosing TBD, including biosensors, and discusses their potential for future use as gold standards in diagnosing these diseases.

Spotted Fever Group Rickettsioses in Central America: The Research and Public Health Disparity among Socioeconomic Lines

Tick-borne diseases including rickettsial diseases are increasing in incidence worldwide. Many rickettsial pathogens can cause disease which is commonly underdiagnosed and underreported; Rickettsia pathogens in the spotted fever group (SFGR) are thus classified as neglected bacterial pathogens. The Central American region shoulders a large proportion of the global neglected disease burden; however, little is known regarding SFGR disease here. Although development varies, four of the seven countries in this region have both the highest poverty rates and SFGR disease burdens (El Salvador, Honduras, Guatemala, and Nicaragua), compared to Belize, Panama, and Costa Rica. Utilizing the Human Development Index (HDI), we compared published articles related to SFGR Rickettsia prevalence in the lowest-HDI-scoring countries to the highest-HDI-scoring countries. Our analysis identified a distinct dichotomy in publication, and by proxy, potentially awareness and knowledge of SFGR tick-borne disease in Central America, where the least-developed countries are at the highest risk for, yet the most vulnerable to, SFGR disease.

Culicidae (Diptera: Culicomorpha) in the southern Brazilian 'Ana Leuch Lozovei' collection, with notes on distribution and diversity

Biological collections are important for acquiring knowledge of the biodiversity of a specific environment. Here, we organize, list and catalog adult specimens of Culicidae from the Parasitology Collection of the Basic Pathology Department at the Federal University of Paraná, Brazil, and present a databank of taxonomic and collection information for each sample. Culicids were collected using different methodologies in 18 municipalities in Paraná state, between 1967 and 1999. There are 5,739 catalogued specimens, of which 4,703 (81.94%) are identified at species level, with a diversity of 100 species. Of these, 18 are new recorded samples for Paraná, and three are new for Brazil. This collection is named the Ana Leuch Lozovei Entomological Collection in honor of the 30 years Prof Lovozei dedicated to culicid study in Paraná. The collection comprises insect vectors or potential vectors, of agents causing human diseases.

Large-scale survey for canine vector-borne parasites in free-ranging dogs and foxes from six diverse bioclimatic regions of Chile

Chile is a large country with a marked range of climate conditions that make it an ideal scenario for the study of vector-borne parasites (VBPs); however, knowledge about their distribution is limited to a few confined areas of this country. The presence of Hepatozoon spp., piroplasmids, Leishmania spp. and filarioids was investigated through molecular and serological methods in blood and serum samples of 764 free-ranging rural dogs, 154 Andean foxes (Lycalopex culpaeus), and 91 South American grey foxes (Lycalopex griseus) from six bioclimatic regions across Chile. Hepatozoon spp. DNA was exclusively detected in foxes (43% prevalence), including sequences closely related to Hepatozoon felis (24.1%; only Andean foxes), Hepatozoon americanum (16.2%; only grey foxes), and Hepatozoon canis (1.25%; in one grey fox). Risk factor assessment identified a higher probability of Hepatozoon infection in juvenile foxes. DNA of piroplasmids was detected in 0.7% of dogs (Babesia vogeli) but in no fox, whilst antibodies against Babesia sp. were detected in 24% of the dogs and 25% of the foxes, suggesting a wider circulation of canine piroplasmids than previously believed. A positive association between the presence of antibodies against Babesia and high Rhipicephalus sanguineus sensu lato burden was observed in dogs. Leishmania spp. DNA and antibodies were detected in 0.8% and 4.4% of the dogs, respectively. Acanthocheilonema reconditum was the only blood nematode detected (1.5% of the dogs and no fox). Differences in prevalence among bioregions were observed for some of the VBPs. These results expand our knowledge about the occurrence of vector-borne parasites in Chile, some of which are firstly reported herein. This information will facilitate the diagnosis of vector-borne diseases in domestic dogs and improve the control measures for both domestic and wild canids.

Novel genotypes of Hepatozoon spp. in small mammals, Brazil

Background

Small mammals (rodents and marsupials) have been poorly explored for the occurrence of apicomplexan (genus Hepatozoon and genera of the order Piroplasmorida) and Anaplasmataceae agents in Brazil. Thus, this study investigated the occurrence of Hepatozoon spp., Piroplasmorida, and Anaplasmataceae agents in small mammals in seven forest fragments in Brazil.

Methods

During 2015–2018, small mammals were captured in six forest fragments in the State of São Paulo (Cerrado and Atlantic Forest biomes) and one fragment in the State of Mato Grosso do Sul (Pantanal biome). Mammal blood, liver, spleen, and lung samples were tested molecularly for the presence of DNA of Hepatozoon, Piroplasmorida, and Anaplasmataceae agents.

Results

A total of 524 mammals were captured, comprising seven species of marsupials, 14 rodents, two carnivores, and one Cingulata. Four novel haplotypes (1, 2, 3, 4) of Hepatozoon spp. were detected in small mammals from different biomes. In São Paulo state, haplotype 1 was detected in rodents from Cerrado and a transition area of Cerrado and Atlantic Forest biomes, whereas haplotype 2 was detected in rodents from the Atlantic Forest biome. On the other hand, haplotypes 3 and 4 were restricted to rodents and marsupials, respectively, from the Pantanal biome of Mato Grosso do Sul. No host species shared more than one haplotype. Despite these distinct geographical and host associations, our phylogenetic analyses indicated that the four Hepatozoon haplotypes belonged to the same clade that contained nearly all haplotypes previously reported on rodents and marsupials, in addition to several reptile-associated haplotypes from different parts of the world. No mammal samples yielded detectable DNA of Piroplasmorida agents. On the other hand, the Anaplasmataceae-targeted polymerase chain reaction (PCR) assay amplified a sequence 100% identical to the Wolbachia pipientis endosymbiont of the rodent filarid Litomosoides galizai.

Conclusions

We report a variety of Hepatozoon haplotypes associated with small mammals in three Brazilian biomes: Cerrado, Atlantic Forest, and Pantanal. Through phylogenetic analyses, the Hepatozoon agents grouped in the rodent-marsupial-reptile large clade of Hepatozoon spp. from the world. The detection of a W. pipientis associated with the rodent filarid L. galizai indicates that the rodent was infected by filarial nematodes.

Graphical Abstract

The emergence of Dirofilaria repens in a non-endemic area influenced by climate change: dynamics of transmission using a mathematical model

Dirofilaria repens is a nematode affecting domestic and wild canids, transmitted by several species of mosquitoes of different genera. It usually causes a non-pathogenic subcutaneous infection in dogs and is the principal agent of human dirofilariasis in the Old World. The geographic distribution of D. repens is changing rapidly, and several factors contribute to the spread of the infection to non-endemic areas. A mathematical model for transmission of Dirofilaria spp. was built, using a system of ordinary differential equations that consider the interactions between reservoirs, vectors, and humans. The transmission simulations of D. repens were carried out considering a projection in time, with intervals of 15 and 100 years. For the dynamics of the vector, seasonal variations were presented as series with quarter periodicity during the year. The results of the simulations highlight the peak of contagions in the reservoir and in humans, a product of the action of the vector when it remains active throughout the year. A 300% infection increase in the reservoir was observed during the first decade and remains present in the population with a representative number of cases. When the vector maintains its density and infectivity during the year, the incidence of the infection in humans increases. Accumulated cases amount to 45 per 100,000 inhabitants, which corresponds to a cumulative incidence of 0.05%, in 85 years. This indicates that early prevention of infection in canids would significantly reduce the disease, also reducing the number of accumulated cases of human dirofilariasis by D. repens. The interaction between the simulations generated by the model highlights the sensitivity of the epidemiological curve to the periodicity of seasonality, reaffirming the hypothesis of the probability of movement of the zoonotic disease to non-endemic areas, due to climate change.

Bartonella henselae Recombinant Pap31 for the Diagnosis of Canine and Human Bartonelloses

Bartonella spp. comprise a genus of Gram-negative alphaproteobacteria that are slow growing, fastidious, and facultative intracellular pathogens with zoonotic potential. Immunofluorescent antibody assays (IFAs), Western blot (WB), and enzyme-linked immunosorbent assays (ELISAs), the frequently used modalities for the serological diagnosis of canine and human Bartonelloses, generate numerous false negative results. Therefore, the development of a reliable serodiagnostic assay for Bartonelloses is of clinical and epidemiological importance. Pap31, a heme binding surface protein of B. henselae, is associated with bacterial adhesion and related to bacterial colonization. To our knowledge, B. henselae Pap31 and its fragments (N-terminal (NTD), middle (MD), and C-terminal (CTD) domains) have not been investigated for the serodiagnosis of canine and human Bartonelloses. In this study, we evaluate the diagnostic utility of B. henselae recombinant whole Pap31 (rPap31) and Pap31 fragments by ELISA using sera from 70 dogs (36 Bartonella spp. IFA-positive (naturally infected), and 34 Bartonella spp. IFA- and PCR-negative (control dogs)) and 36 humans (18 Bartonella spp. IFA-positive (naturally infected) and 18 controls)). In the dogs, the area under the curve (AUC) score of recombinant whole Pap31 was 0.714 with a sensitivity of 42% and specificity of 94% at an OD cutoff value of 0.8955. Among the evaluated recombinant Pap31 proteins for the diagnosis of canine Bartonelloses, rPap31-NTD yielded the highest AUC score of 0.792 (95% CI 0.688-0.895) with a sensitivity of 44% and specificity of 100% at a cutoff value of 1.198. In concordance with this finding, rPap31-NTD also had the highest AUC score of 0.747 (95% CI 0.581-0.913) among the Pap31 recombinant proteins for the diagnosis of human Bartonelloses, with 39% sensitivity and 94% specificity at a cutoff value of 1.366. Recombinant whole Pap31 (rPap31) resulted in 72% sensitivity and 61% specificity at a cutoff value of 0.215 for human Bartonelloses. Due to either low sensitivity or questionable specificity, our findings indicate that recombinant Pap31 and the selected fragments may not be appropriate diagnostic targets in detecting anti-Bartonella antibodies in Bartonella-infected dogs and humans. The findings from this study can be used to further assess the antigenicity and immunogenicity of B. henselae Pap31 as a diagnostic target.

Molecular characterization of canine filarioids in a previously non-endemic area of Rio de Janeiro State, Brazil

Dirofilaria immitis is the causative agent of canine heartworm disease, a severe health problem in dogs, especially in coastal areas of tropical and subtropical regions of the world. We employed molecular methods to investigate the occurrence of canine infection by filarioids in five municipalities of Baixada Fluminense (Magé, Duque de Caxias, Guapimirim, Nova Iguaçu, and São João de Meriti), a non-endemic area of Rio de Janeiro State, Southeast Brazil. A total of 110 canine blood samples collected from 2017 to 2018 and positive for microfilariae at the modified Knott's test were screened by cPCR targeting DNA fragments of the 12S rDNA gene for filarial nematodes. Seventy-seven samples (70%) tested positive at the molecular analysis. Of these, 72 were identified as D. immitis and 5 (4.5%) as Acanthocheilonema reconditum. Dirofilaria repens was not detected in the studied municipalities of Baixada Fluminense. This is the first record of D. immitis and A. reconditum in the Baixada Fluminense region, Rio de Janeiro State, Brazil. The prevalence of D. immitis cases in the five municipalities suggests the establishment and maintenance of its enzootic cycle in the studied region, which indicate vulnerability to the occurrence of epidemic cycles and, possibly, human cases.

Canine and Feline Parasitology: Analogies, Differences, and Relevance for Human Health

Cats and dogs are treated as family members by most pet owners. Therefore, a high quality of veterinary care and preventive medicine is imperative for animal health and welfare and for the protection of humans from zoonotic pathogens. There is a general perception of cats being treated as "small dogs," especially in the field of clinical parasitology. As a result, several important differences between the two animal species are not taken into proper consideration and are often overlooked. Dogs and cats are profoundly different under evolutionary, biological, ethological, behavioral, and immunological standpoints. These differences impact clinical features, diagnosis, and control of canine and feline parasites and transmission risk for humans. This review outlines the most common parasitoses and vector-borne diseases of dogs and cats, with a focus on major convergences and divergences, and discusses parasites that have (i) evolved based on different preys for dogs and cats, (ii) adapted due to different immunological or behavioral animal profiles, and (iii) developed more similarities than differences in canine and feline infections and associated diseases. Differences, similarities, and peculiarities of canine and feline parasitology are herein reviewed in three macrosections: (i) carnivorism, vegetarianism, anatomy, genetics, and parasites, (ii) evolutionary adaptation of nematodes, including veterinary reconsideration and zoonotic importance, and (iii) behavior and immune system driving ectoparasites and transmitted diseases. Emphasis is given to provide further steps toward a more accurate evaluation of canine and feline parasitology in a changing world in terms of public health relevance and One Health approach.

Current distribution of selected canine vector-borne diseases in domestic dogs from Barranquilla and Puerto Colombia, Atlántico, Colombia

Background

Climate change, the increase of travel with infected animals from endemic areas, the introduction of new vectors in these areas and environmental changes caused by human activity, among other factors, have contributed to the establishment and increase of canine vector‐borne diseases (CVBDs), several of which are zoonotic and pose a risk to the human population. In Colombia, there are very few studies that address the prevalence of these diseases. The objective of this study was to update the prevalence of cardiopulmonary dirofilariosis, anaplasmosis, ehrlichiosis and Lyme borreliosis in dogs in Barranquilla and Puerto Colombia, areas of northern Colombia.

Materials and methods

The present study included 354 dogs presented to veterinary clinics for routine health examination and foundations for stray dogs between November 2016 and July 2018.

Results

The percentage of dogs positive for Ehrlichia spp. was 61.86%, followed by 22.03% for Anaplasma spp., 11.30% positive for Dirofilaria immitis antigens and 0.56% positive for Borrelia burgdorferi. In addition, several dogs positive for antibodies against two or more infectious diseases were found. Higher seroprevalences were documented in outdoor dogs compared to indoor‐housed dogs.

Conclusion

These results suggest that veterinarians should routinely implement prophylactic programmes for these CVBDs, particularly for dogs that reside outdoors.

Microscopic Detection, Hematological Evaluation and Molecular Characterization of Piroplasms from Naturally Infected Dogs in Rio de Janeiro, Brazil

PURPOSE

This study aimed to analyze the frequency of piroplasmids in the blood of dogs in Rio de Janeiro, compare the performance of microscopic techniques, assess the risk factors associated with infections and also molecularly and morphologically characterize the piroplasmids identified.

METHODS

In all, 407 blood samples were collected from dogs between 2018 and 2019. These were subjected to microscopic parasitological techniques for thin and thick smears, stained with Giemsa and using a rapid staining kit. The slides were read under an optical microscope and the protozoa were characterized morphometrically. In addition, the blood samples were subjected to molecular characterization for diagnosing piroplasmid species using primers that amplified the gene 18S rRNA.

RESULTS

Piroplasmids were detected in 38 (9.3%) samples. Of these, 33 samples presented nucleotide sequences compatible with Babesia vogeli. Most of the positive samples were young, male, defined breeds dogs that had been attended in clinics in São Gonçalo city. Thrombocytopenia and leukopenia were the hematological alterations more observed in positive samples, but positive samples without alterations were also detected. The sex was the only variable that showed statistical differences. Males dogs being more often infected than females (p < 0.05). The microscope slides mostly showed piriform and oval merozoites measuring greater than 2.5 µm in length, which were compatible with B. vogeli. However, smaller forms were also identified, thus demonstrating the polymorphic nature of this parasite.

CONCLUSION

Babesia vogeli was detected in blood samples from dogs in the metropolitan cities of Rio de Janeiro by molecular techniques in different parasite morphotypes.

Infection with Dirofilaria immitis and Other Infections in Cats and Dogs from Rio de Janeiro, Brazil: The Need for Prophylactic Enforcement

PURPOSE

Dirofilaria immitis, a mosquito-borne nematode that primarily infects dogs, can equally infect cats. Although there have been numerous studies on canine heartworm prevalence in Brazil, there have been few studies on feline infections. Feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) are both life-threatening retroviruses transmitted directly between cats. Infections with Ehrlichia spp. and Anaplasma spp. are highly prevalent among dogs in Brazil, with Rhipicephalus sanguineus being the main vector for both bacteria. This study aimed to gather information on these infections among dogs and cats in the metropolitan area of Rio de Janeiro by performing rapid point-of-care tests for prophylactic enforcement.

METHODS

Surplus samples of serum or plasma from private laboratories were tested by enzyme-linked immunosorbent assay (ELISA) (SNAP Feline Triple Test or SNAP 4Dx Plus Test).

RESULTS

The prevalence of heartworm disease was 7% among dogs and 0.9% among cats, the latter being 12.9% of the former. The prevalence of FIV and FeLV was 4.3 and 11.9%, respectively. Among dogs, the seroprevalence of Ehrlichia spp. and Anaplasma spp. was 27.1 and 9.8%, respectively, and Borrelia burgdorferi was not detected.

CONCLUSION

Given that such infections circulate among pets, prophylactic measures should be encouraged by small animal practitioners.

Heartworm disease - Overview, intervention, and industry perspective

Dirofilaria immitis, also known as heartworm, is a major parasitic threat for dogs and cats around the world. Because of its impact on the health and welfare of companion animals, heartworm disease is of huge veterinary and economic importance especially in North America, Europe, Asia and Australia. Within the animal health market many different heartworm preventive products are available, all of which contain active components of the same drug class, the macrocyclic lactones. In addition to compliance issues, such as under-dosing or irregular treatment intervals, the occurrence of drug-resistant heartworms within the populations in the Mississippi River areas adds to the failure of preventive treatments. The objective of this review is to provide an overview of the disease, summarize the current disease control measures and highlight potential new avenues and best practices for treatment and prevention.

Molecular epidemiology and prevalence of babesial infections in dogs in two hyperendemic foci in Brazil

Babesial parasites are some of the most ubiquitous blood pathogens and consequently have considerable worldwide veterinary impact. Dogs living in the tropics are highly exposed to babesial parasites, particularly to Babesia vogeli. Limited data on the seroprevalence and molecular prevalence of Babesia spp. in dogs are available in Latin America. We conducted a cross-sectional study combining serological and molecular tests to estimate the seroprevalence and molecular epidemiology of Babesia spp. infections in dogs in two hyperendemic foci in Brazil. A total of 630 privately owned dogs (417 from Goiana municipality, Pernambuco state, north-eastern Brazil, and 213 from São Joaquim de Bicas municipality, Minas Gerais state, south-eastern Brazil) were sampled and molecularly and serologically tested for Babesia spp. Overall, 519 dogs (82.4%) presented detectable IgG antibodies against Babesia spp., and seropositivity was significantly higher in dogs older than 1 year. Molecularly, 34 dogs (5.4%) were positive for a ~ 200 bp fragment of the 18S rRNA gene of Babesia spp. and 88 (14.0%) for a longer fragment (~ 450 bp) of the same gene of Babesia spp. and other protozoa. The 18S rRNA gene sequences generated herein corresponded to B. vogeli (n = 52) or Hepatozoon canis (n = 20). This study confirms a high level of exposure to B. vogeli in two areas of Brazil and highlights that most of the dogs living in these areas are infected during the course of their life, reflected by increased seroprevalence in older dogs. Increased awareness and prevention of tick-borne protozoa infections in dogs from Brazil and Latin America are urgently needed.

Mapping the distribution and risk factors of Anaplasmataceae in wild and domestic canines in Chile and their association with Rhipicephalus sanguineus species complex lineages

Anaplasma platys and Ehrlichia canis are members of the Anaplasmataceae family that cause disease in dogs and are mainly transmitted by Rhipicephalus sanguineus species group ticks. We performed a cross-sectional study on these pathogens across six bioclimatic regions of Chile, including 719 free-ranging rural dogs, 132 Andean foxes (Lycalopex culpaeus), and 82 South American gray foxes (Lycalopex griseus). Dog and fox blood samples were first screened for DNA of Anaplasmataceae followed by two Ehrlichia-specific protocols. Antibodies against Anaplasma sp. and E. canis were assessed by immunofluorescence in dogs. Ectoparasites were collected and identified, with the determination of the lineages of the Rhipicephalus sanguineus species group by molecular and phylogenetic analyses. Finally, potential risk factors for infection were investigated across the different bioclimatic regions and host species. All DNA amplicons obtained from the screening protocol corresponded to Anaplasma platys. The occurrence of both A. platys DNA and antibodies was confirmed in all six bioclimatic regions, except for regions at high altitude and/or without either R. sanguineus species group lineage present. Dogs infested with R. sanguineus ticks were significantly more prone to be infected and exposed to Anaplasma spp. Prevalence of DNA was significantly higher in juvenile (19%) than in adult dogs (9%), whereas the opposite was found for seroprevalence (19% versus 35%, respectively). Overall prevalence of A. platys DNA was higher in dogs (11%) than in foxes (4%), probably owing to markedly lower tick infestations in the foxes. Ehrlichia canis DNA was not detected in any sample, and antibodies against this pathogen were detected only in four dogs, in areas with both R. sanguineus lineages present. Free-ranging dogs in Chile could be favoring the maintenance of A. platys in all areas suitable for its tick vector. Although apparently infrequent, spillovers from dogs to foxes may be taking place and should be considered in management plans in Chile.

Molecular detection and identification of spotted fever group rickettsiae in ticks collected from horses in Cuba

Spotted fever group (SFG) rickettsiae are obligatory intracellular bacteria that cause disease in humans and other animals. Ixodid ticks are the principal vectors of SFG rickettsiae. The present study aimed to determine the prevalence and species identity of SFG rickettsiae in ticks and horses from urban and rural areas of western Cuba using PCR assays. Tick samples, collected from 79 horses, consisted of 14 Amblyomma mixtum adults, 111 Dermacentor nitens adults and 19 pools of D. nitens nymphs (2-5 individuals/pool). The PCR results revealed the presence of Rickettsia spp. in 64% of the A. mixtum adults, 16% of the D. nitens adults, and 11% of the pooled samples of D. nitens nymphs. In contrast, Rickettsia spp. was not detected in any of the 200 horse blood samples included in this study. DNA sequence data of the rickettsial 17 kDa antigen gene showed that Rickettsia amblyommatis was present in A. mixtum; and Rickettsia felis in D. nitens. This is the first report of R. felis in D. nitens in Cuba. The present study extends our knowledge of the potential vector spectrum and distribution of SFG rickettsiae pathogens in western Cuba.

Serological and Molecular Evidence of Patients Infected with Anaplasma phagocytophilum in Mexico

Human granulocytic Anaplasmosis (HGA), is a tick-borne infectious disease transmitted by ticks, resulting in acute feverish episodes. The etiological agent is the bacteria Anaplasma phagocytophilum; which is spread by ticks of the genus Ixodes spp. to complete its life cycle. In Mexico, there is only one case report. The primary challenge is understanding how other bacteria affect or overlap with the clinical manifestation of the disease. Sample collection occurred over the period September 2017 through October 2019. Blood samples from human subjects were obtained immediately after they signed consent forms. We analyzed for the presence for A. phagocytophilum by serological (IFA IgG two times) and PCR targeting 16SrRNA and groEL genes, followed by DNA sequencing. All patients with a history of travel abroad were dismissed for this project. In total, 1924 patients participated and of these, 1014 samples across the country were analyzed. Of these, 85 (8.38%) had IFA results that ranged from 1:384 to 1:896. Of the positive samples, 7.10% were used for PCR. Significant clinical manifestations included: dizziness, nausea, petechial, epistaxis, enlarged liver and/or spleen and thrombocytopenia. Hospitalization of at least 1.5 days was necessary for 3.2% of patients. None of the cases analyzed were lethal. This is the first clinical manifestations along with serological test results and molecular analysis confirmed the presence of A. phagocytophilum resulting in HGA in patients from Mexico. Health institutions and medical practitioners in general should include diagnostic testing for HGA among high risk populations and should recognize it as a vector-borne emerging infectious disease in Mexico.

Trypanosoma cruzi co-infections with other vector borne diseases are frequent in dogs from the pacific coast of Ecuador

Dogs are a reservoir for Chagas disease, caused by Trypanosoma cruzi (T. cruzi), and other companion vector-borne diseases, including ehrlichiosis (Ehrlichia canis and Ehrlichia ewingii), anaplasmosis (Anaplasma phagocytophilum and Anaplasma platys), dirofilariasis (Dirofilaria immitis) and Lyme disease (Borrelia burgdorferi). This study has two key objectives: 1) to determine seroreactivity against T. cruzi in dogs from the town of Colón, in Portoviejo city, in the central coast of Ecuador; and 2) to establish the coinfection frequency of other companion vector-borne diseases in dogs positive for T. cruzi. Antibodies against T. cruzi were detected using two enzyme-linked immunosorbent assays. Diagnostic consensus between ELISA tests was established using the Cohen's Kappa coefficient. Other haemoparasitic diseases were detected using the IDEXX SNAP® 4Dx® kit in dogs previously diagnosed as T. cruzi-seropositive. From 84 dogs sampled, 57.14% (48/84) tested positive for T. cruzi. Co-infection analysis of 25 dogs positive for T. cruzi revealed antibodies also against Ehrlichia spp. (48%), Anaplasma spp. (28%), and Dirofilaria immitis (12%). These results provide a novel perspective regarding the status of these pathogens which co-infect dogs in Colón. Since all these pathogens are zoonotic, our findings should warn regional health authorities to implement sanitary programs, to better prevent and control vectors associated to these pathogens. On the other hand, human and veterinarian doctors, should consider that patients with a cardiac infection condition could be suffering co-infections with two or more vector transmitted pathogens.

Demographic and Pathogens of Domestic, Free-Roaming Pets and the Implications for Wild Carnivores and Human Health in the San Luis Region of Costa Rica

Habitat loss and degradation, restricted ranges, prey exploitation, and poaching are important factors for the decline of several wild carnivore populations and additional stress from infectious agents is an increasing concern. Given the rapid growth of human populations in some regions like Costa Rica, pathogens introduced, sustained, and transmitted by domestic carnivores may be particularly important. To better understand the significance of domestic carnivore pathogens for wildlife, we determine the prevalence of infection and possible mechanisms for contact between the two groups. The demographics, role in the household, and pathogens of pet dogs and cats was studied during three annual spay/neuter clinics in San Luis, Costa Rica. Most dogs were owned primarily as pets and guard animals, but ~10% were used for hunting. Cats were owned primarily as pets and for pest control. Both roamed freely outdoors. We detected high prevalences of some pathogens (e.g., carnivore protoparvovirus 1 and Toxoplasma gondii). Some pathogens are known to persist in the environment, which increases the probability of exposure to wild carnivores. This study demonstrated that domestic pets in San Luis, home to a number of protected and endangered wildlife species, are infected with pathogens to which these wild species are potentially susceptible. Additionally, results from our questionnaire support the potential for domestic and wild animal contact, which may result in disease spillover.

Canine and feline vector-borne diseases of zoonotic concern in Southeast Asia

Dogs and cats are important hosts and reservoirs of many viral, bacterial, protozoal, and helminthic pathogens transmitted by arthropods, including some of zoonotic concern. By sharing the same environment, these companion animals play an important role in the transmission of zoonotic pathogens to humans in various regions and socioeconomic contexts. While canine and feline vector-borne diseases (VBD) are of major concern in wealthy regions (e.g. Europe and North America), less attention has been received in developing countries such as those in Southeast Asia (SEA). This review provides summarized and updated information on canine and feline VBD with emphasis on those of zoonotic concern in SEA. Of these, zoonotic bacteria (i.e. Bartonella henselae, Bartonella clarridgeiae, and Rickettsia felis) and filarial nematodes (i.e. Brugia malayi, Dirofilaria repens, and Dirofilaria immitis) stand out as the most important in veterinary and human medicine. Additionally, the recent finding of Leishmania infantum in dogs in SEA raised more concerns about the spreading of this zoonotic agent in this region. Further epidemiological surveys, especially in countries with extremely scant information such as Cambodia, Laos, Myanmar, and Timor-Leste are advocated. Additionally, effective control measures of canine and feline VBD as well as their arthropod vectors should be simultaneously performed for the management of zoonotic infections.

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Many canine and feline vector-borne infections affect animals and humans in Southeast Asia.

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Ticks, fleas and mosquitoes are the most common vectors transmitting pathogens to dogs, cats and humans in Southeast Asia.

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Bartonella henselae, Rickettsia felis and Dirofilaria repens are of concern to human health in this region.

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Collaboration between governments and researchers is encouraged for a better management of vector-borne diseases.

Arthropod-Borne Pathogens in Stray Cats from Northern Italy: A Serological and Molecular Survey

Cats may be affected by a wide range of arthropod-borne pathogens (ABPs) of medical and veterinary interest. Between February 2018 and October 2019, 85 blood samples were collected from stray cats from the Emilia Romagna region (northern Italy). Ticks (n = 28) on the examined cats were also collected. Serological and molecular methods were applied to search for infection by Anaplasma phagocytophilum, Bartonella henselae, Coxiella burnetii, Ehrlichia canis, Leishmania spp., Babesia spp., Hepatozoon spp., and Cytauxzoon spp. A total of 71 sera (83.5%) had antibodies to at least one investigated pathogen: 39 (45.9%) were positive for B. henselae, 32 (37.6%) positive for C. burnetii, 12 (14.1%) positive for E. canis, four (4.7%) positive for A. phagocytophilum, and two (2.4%) positive for Leishmania spp. A total of 47 (55.3%) DNA samples were positive by PCR for at least one investigated pathogen: 25 (29.4%) were positive for C. burnetii, 23 (27.1%) positive for B. henselae, two (2.4%) positive for E. canis, five (5.9%) positive for Leishmania spp., and two (2.4%) positive for Cytauxzoon spp. Coinfections were observed in 21 cats (24.7%). No positivity was found for A. phagocytophilum, Babesia spp., or Hepatozoon spp. All ticks were negative. A widespread presence of ABPs in the investigated area of northern Italy was shown. Accurate information on their prevalence may be relevant for feline veterinary medicine, as well as from a One Health perspective.