An investigation on vertical transmission of Leishmania infantum in experimentally infected dogs and assessment of offspring's infectiousness potential by xenodiagnosis

Transmission Dynamics of Punique Virus in Tunisia

A novel phlebovirus, Punique virus (PUNV), was discovered and isolated in 2008 from sandflies from Northern Tunisia. PUNV is now classified as a unique member of the Punique phlebovirus species within the Phlebovirus genus in the Phenuiviridae family (order bunyavirales). In this study, we aimed to investigate the transmission dynamics of PUNV in Tunisia. Sandflies were collected during two consecutive years, 2009 and 2010, by CDC light traps. In 2009, a total of 873 sandflies were collected and identified to the species level. Phlebotomus perniciosus was the most abundant species. One pool of P. perniciosus females collected in autumn contained PUNV RNA, yielding an infection rate of 0.11%. The population densities of circulating sandfly species were assessed during May–November 2010 in Northern Tunisia by using sticky traps. Phlebotomus (Larroussius) perniciosus (71.74%) was the most abundant species, followed by Phlebotumus (Larroussius) longicuspis (17.47%), and Phlebotumus (Larroussius) perfiliewi (8.82%). The densities of dominant sandfly species were found to peak in early spring and again in the autumn. In 2010, species identification was not performed, and sandflies were only discriminated on the basis of sex and collection date. Out of 249 pools, three contained PUNV RNA. Each positive pool allowed virus isolation. The three pools of female sandflies containing PUNV RNA were collected in autumn with an infection rate of 0.05%. These findings provide further evidence that P. perniciosus is the main vector of PUNV in Tunisia, and this phlebovirus is endemic in Tunisia. Our findings provided strong evidence of intensive circulation of PUNV in sandflies and hosts through a viral infection buildup process between sandfly vectors and hosts starting at the beginning of the activity of sandflies in spring to reach a maximum during the second main peak in autumn.

Canine leishmaniosis in Tunisia: Growing prevalence, larger zones of infection

Background

Discovered by Nicolle and Comte in 1908 in Tunisia, Leishmania infantum is an intracellular protozoan responsible for zoonotic canine leishmaniosis (CanL) and zoonotic human visceral leishmaniasis (HVL). It is endemic in several regions of the world, including Tunisia, with dogs considered as the main domestic reservoir. The geographic expansion of canine leishmaniosis (CanL) has been linked to global environmental changes that have affected the density and the distribution of its sand fly vectors.

Methodology/Principal findings

In this study, a cross-sectional epidemiological survey on CanL was carried out in 8 localities in 8 bioclimatic areas of Tunisia. Blood samples were taken from 317 dogs after clinical examination. Collected sera were tested by indirect fluorescent antibody test (IFAT; 1:80) for the presence of anti-Leishmania infantum antibodies. The overall seroprevalence was 58.3% (185/317). Among positive dogs, only 16.7% showed clinical signs suggestive of leishmaniosis. Seroprevalence rates varied from 6.8% to 84.6% and from 28% to 66% by bioclimatic zone and age group, respectively. Serological positivity was not statistically associated with gender. The presence of Leishmania DNA in blood, using PCR, revealed 21.2% (64/302) prevalence in dogs, which varied by bioclimatic zone (7.3% to 31%) and age group (7% to 25%). The entomological survey carried out in the studied localities showed 16 species of the two genera (Phlebotomus and Sergentomyia). P. perniciosus, P. papatasi, and P. perfiliewi were the most dominant species with relative abundances of 34.7%, 25% and 20.4%, respectively.

Conclusions/Significance

The present report suggests a significant increase of CanL in all bioclimatic areas in Tunisia and confirms the ongoing spread of the infection of dogs to the country’s arid zone. Such an expansion of infection in dog population could be attributed to ecological, agronomic, social and climatic factors that affect the presence and density of the phlebotomine vectors.

Visceral leishmaniasis caused by Leishmania infantum is an endemic disease in several regions of the world, especially, in the Mediterranean basin, where dogs constitute the main domestic reservoir for humans. This zoonotic vector-borne disease is closely associated with the environment.

We carried out studies in 8 different regions of Tunisia, collecting and testing blood samples from 317 dogs. Out of which, more than half (58.3%) tested positive for L. infantum (IFAT+), although, only one-third of these displayed clinical signs. However, the detection of Leishmania DNA by blood PCR revealed a global prevalence in dogs of 21.2% (64/302) with a variation between bioclimatic zones. Our entomological survey revealed 16 sand fly species, dominated by the Phlebotomus and Sergentomyia genera, of which the most dominant were P. perniciosus, P. perfiliewi and P. papatasi. The first two of these are recognized vectors of L. infantum. Canine leishmaniosis continues to spread across Tunisia, moving southward, to arid zones because of global warming and agronomic and social factors affecting the presence and density of the phlebotomine vectors.

Canine leishmaniasis in Balkan - A review of occurrence and epidemiology

Canine leishmaniasis is a parasitic zoonotic infection of dogs caused by the Leishmania spp. parasites. In Europe, canine leishmaniasis is among the most important vector-borne parasitic diseases of dogs, with majority of data originating from countries of southwestern Europe. With its scarce and outdated records, the Balkan region presents the "blank space" in the European map of canine leishmaniasis knowledge. Numerous records obtained during the past decade and a half indicate the emergence of autochthonous canine leishmaniasis in new settings all across Balkan, a significant increase in the numbers of infected dogs in previously endemic areas, and northward spread of the disease. As the majority of canine leishmaniasis data from Balkan countries are several decades old and generally written in native Balkan languages, hence not available to the broader area of scientists, comprehensive search of scientific literature published from 1934 to January 2021 was conducted in order to provide a better perspective to the past and current canine leishmaniasis situation in Balkan. This review provides exhaustive information on all leishmaniasis records in dogs, wild animals and cats, available from 10 countries of the Balkan region. It identifies dogs as the main disease reservoirs and highlights the importance of wild animals, and potentially cats, as disease reservoirs, which is of great public and veterinary health concern. Additionally, certain shortcomings in canine leishmaniasis research, management, surveillance and control were identified.

Leishmania infantum xenodiagnosis from vertically infected dogs reveals significant skin tropism

BACKGROUND

Dogs are the primary reservoir for human visceral leishmaniasis due to Leishmania infantum. Phlebotomine sand flies maintain zoonotic transmission of parasites between dogs and humans. A subset of dogs is infected transplacentally during gestation, but at what stage of the clinical spectrum vertically infected dogs contribute to the infected sand fly pool is unknown.

METHODOLOGY/PRINCIPAL FINDINGS

We examined infectiousness of dogs vertically infected with L. infantum from multiple clinical states to the vector Lutzomyia longipalpis using xenodiagnosis and found that vertically infected dogs were infectious to sand flies at differing rates. Dogs with mild to moderate disease showed significantly higher transmission to the vector than dogs with subclinical or severe disease. We documented a substantial parasite burden in the skin of vertically infected dogs by RT-qPCR, despite these dogs not having received intradermal parasites via sand flies. There was a highly significant correlation between skin parasite burden at the feeding site and sand fly parasite uptake. This suggests dogs with high skin parasite burden contribute the most to the infected sand fly pool. Although skin parasite load and parasitemia correlated with one another, the average parasite number detected in skin was significantly higher compared to blood in matched subjects. Thus, dermal resident parasites were infectious to sand flies from dogs without detectable parasitemia.

CONCLUSIONS/SIGNIFICANCE

Together, our data implicate skin parasite burden and earlier clinical status as stronger indicators of outward transmission potential than blood parasite burden. Our studies of a population of dogs without vector transmission highlights the need to consider canine vertical transmission in surveillance and prevention strategies.

Investigation of canine visceral leishmaniasis in a non-endemic area in Brazil and the comparison of serological and molecular diagnostic tests

INTRODUCTION:

Visceral leishmaniasis (VL) is an important zoonosis in Brazil. Previous identification of parasitized dogs can also help prevent the disease in humans, even in non-endemic areas of the country. The Brazilian Ministry of Health recommends diagnosis in dogs using a DPP^® (rapid test) as a screening test and an immunoenzymatic assay (ELISA) as a confirmatory test (DPP^®+ELISA), and culling infected dogs as a legal control measure. However, the accuracy of these serological tests has been questioned.

METHODS:

VL in dogs was investigated in a non-endemic area of the São Paulo state for three consecutive years, and the performances of different diagnostic tests were compared.

RESULTS:

A total of 331 dog samples were collected in 2015, 373 in 2016, and 347 in 2017. The seroprevalence by DPP^®+ELISA was 3.3, 3.2, and 0.3%, respectively, and by indirect immunofluorescence assay (IFA), it was 3.0, 5.6, and 5.5%, respectively. ELISA confirmed 18.4% of DPP^® positive samples. The concordance between the IFA and DPP^® was 83.9%. The concordance between IFA and DPP^®+ELISA was 92.9%. A molecular diagnostic test (PCR) was performed in 63.2% of the seropositive samples, all of which were negative.

CONCLUSIONS:

In non-endemic areas, diagnostic tests in dogs should be carefully evaluated to avoid false results.

Enhanced attraction of sand fly vectors of Leishmania infantum to dogs infected with zoonotic visceral leishmaniasis

BACKGROUND

The sand fly Phlebotomus perniciosus is the main vector of Leishmania infantum, etiological agent of zoonotic visceral leishmaniasis in the Western Mediterranean basin. Dogs are the main reservoir host of this disease. The main objective of this study was to determine, under both laboratory and field conditions, if dogs infected with L. infantum, were more attractive to female P. perniciosus than uninfected dogs.

METHODOLOGY/PRINCIPAL FINDINGS

We carried out a series of host choice experiments and found that infected dogs were significantly more attractive to P. perniciosus than uninfected dogs in the laboratory as well as in the field. Significantly more P. perniciosus fed on infected dogs than on uninfected dogs. However, the fecundity of P. perniciosus fed on infected dogs was adversely impacted compared to uninfected dogs by lowering the number of laid eggs. Phlebotomus perfiliewi, the second most abundant sand fly species in the field site and a competent vector of L. infantum had similar trends of attractivity as P. perniciosus toward infected dogs under field conditions.

CONCLUSIONS

The results strongly suggest that L. infantum causes physiological changes in the reservoir host which lead to the host becoming more attractive to both male and female P. perniciosus. These changes are likely to improve the chance of successful transmission because of increased contact with infected hosts and therefore, infected dogs should be particularly targeted in the control of zoonotic visceral leishmaniasis in North Africa.

Early onset of clinical leishmaniosis in a litter of pups with evidence of in utero transmission

Background

Canine leishmaniosis (CanL) is a zoonotic disease caused by Leishmania infantum. Although usually transmitted by phlebotomine sand flies, infection by vertical transmission and by blood transfusion have also been reported.

Methods

We describe the very early onset of clinical leishmaniosis, starting from 2 months of age, in a litter of pups born to an infected dam and sire. Seven pups from the litter of nine living in different households showed alopecic, exfoliative dermatitis and ulcerative cutaneous lesions. All pups and both parents were tested on at least one occasion both serologically, by enzyme-linked immunosorbent assay (ELISA), and by polymerase chain reaction (PCR) targeting the Leishmania ribosomal operon internal transcribed spacer 1 region and a short fragment of the kinetoplast minicircle; positive amplicons were sequenced.

Results

All nine pups were PCR positive for L. infantum verified by DNA sequencing, seven were positive by conjunctival, five by blood, four by lymph node, and one by skin PCR from an ulcerative lesion. Both pups with no clinical signs were seronegative, while five of the seven pups with dermatologic abnormalities were seropositive by ELISA. The sire had typical clinical dermatologic and visceral findings of CanL, was seropositive and PCR positive for L. infantum in the lymph node and fluid from the vas deferens tested after the testes were removed by castration. The dam was sub-clinically infected and seronegative, but positive by blood, lymph node and conjunctival PCR for L. infantum. Allopurinol administered to all clinically affected dogs resulted in clinical recovery.

Conclusions

Infection with L. infantum in both parents, the very early age of clinical onset among most of the pups, and the fact that the puppies were born and detected with signs of leishmaniosis in the winter, which is a season without sand fly activity in Israel, strongly suggest vertical transmission. Awareness of the possibility of vertical transmission of L. infantum and infection in littermates should be increased. It is recommended that littermates of young dogs with clinical leishmaniosis should be tested for sub-clinical infection as they may also be infectious to sand flies and thus to other dogs and to humans. Restricting the mating of infected bitches should also be considered to prevent the vertical transmission of the infection.

Graphic abstract

Demographics and travel history of imported and autochthonous cases of leishmaniosis in dogs in the United States and Canada, 2006 to 2019

BACKGROUND

Leishmania infantum infections are reported in foxhounds throughout the United States (US) and Canada, but only rarely in other dog breeds. A seroprevalence report from 2006 documented leishmaniosis in foxhounds (8.9%) tested in the US between 2000 and 2003. All other breeds were seronegative.

OBJECTIVE

To reexamine demographics and travel history of L. infantum-infected dogs in the US and Canada, we hypothesize detection of L. infantum in more foxhounds than nonfoxhounds and that infected nonfoxhounds will have traveled to endemic regions.

ANIMALS

A total of 125 dogs positive for L. infantum by immunofluorescent antibody, PCR, or both.

METHODS

Retrospective, descriptive study of L. infantum-infected dogs between 4 January 2006 and 22 May 2019. Travel history and known lineage to foxhounds was collected from questionnaires.

RESULTS

Leishmania infantum was detected in 125 (6.4%) of 1961 dogs tested between 4 January 2006 and 22 May 2019, of which 10 (8%) were foxhounds and 115 (92%) were nonfoxhound breeds. Travel history available for 69 (55%) dogs showed 60 (86.9%) dogs had traveled outside of the US or Canada. Nine (13%) dogs had not traveled outside of the US or Canada, 5 of which were nonfoxhounds.

CONCLUSIONS AND CLINICAL IMPORTANCE

The majority of L. infantum cases were detected in nonfoxhounds, many of which had traveled to L. infantum-endemic countries, and several nonfoxhound breeds had no travel history. Leishmania surveillance should be considered for dogs that return from L. infantum-endemic regions to monitor emergence of this zoonotic disease in the US and Canada.

The limited knowledge of placental damage due to neglected infections: ongoing problems in Latin America

The placenta works as a selective barrier, protecting the fetus from potential infections that may affect the maternal organism during pregnancy. In this review, we will discuss several challenging infections that are common within Latin American countries and that may affect the maternal-fetal interface and pose risks to fetal development. Specifically, we will focus on emerging infectious diseases including the arboviruses, malaria, leishmaniasis, and the bacterial foodborne disease caused by Shiga toxin-producing Escherichia coli. We will also highlight some topics of interest currently being studied by research groups that comprise an international effort aimed at filling the knowledge gaps in this field. These topics address the relationship between exposure to microorganisms and placental abnormalities, congenital anomalies, and complications of pregnancy.

ABBREVIATIONS

ADE: antibody-dependent enhancement; CCL2: monocyte chemoattractant protein-1; CCL3: macrophage inflammatory protein-1 α; CCL5: chemokine (C-C motif) ligand 5; CHIKV: chikungunya virus; DCL: diffuse cutaneous leishmaniasis; DENV: dengue virus; Gb3: glycolipid globotriaosylceramyde; HIF: hypoxia-inducible factor; HUS: hemolytic uremic syndrome; IFN: interferon; Ig: immunoglobulins; IL: interleukin; IUGR: intrauterine growth restriction; LCL: localized cutaneous leishmaniasis; LPS: lipopolysaccharid; MCL: mucocutaneous leishmaniasis; NO: nitric oxide; PCR: polymerase chain reaction; PGF: placental growth factor; PM: placental malaria; RIVATREM: Red Iberoamericana de Alteraciones Vasculares em transtornos del Embarazo; sVEGFR: soluble vascular endothelial growth factor receptor; STEC: shiga toxin-producing Escherichia coli; stx: shiga toxin protein; TNF: tumor necrosis factor; TOAS: T cell original antigenic sin; Var2CSA: variant surface antigen 2-CSA; VEGF: vascular endothelial growth factor; VL: visceral leishmaniasis; WHO: world health organization; YFV: yellow fever virus; ZIKV: Zika virus.

Frequency, active infection and load of Leishmania infantum and associated histological alterations in the genital tract of male and female dogs

Visceral leishmaniasis caused by the protozoan Leishmania infantum is a zoonosis. The domestic dog is the primary reservoir in urban areas. This study aimed to evaluate the frequency, active infection and load of L. infantum in the genital tract of male and female dogs seropositive for this parasite, as well as to identify histological genital alterations associated with this protozoan. We studied 45 male and 25 female L. infantum-seropositive noncastrated dogs from the same endemic area in Brazil. Tissue samples from the testis, epididymis, prostate, vulva, vagina, and uterus were examined by singleplex qPCR and parasitological tests (histopathology, immunohistochemistry, and parasitological culture). The latter were performed for the detection of active infection (parasites able to multiply and to induce lesions). Forty-four (98%) males and 25 (100%) females were positive for L. infantum in the genital tract (epididymis: 98%; vulva: 92%; vagina: 92%; testis: 91%; uterus: 84%; prostate: 66%). Active infection in the genital tract was confirmed in 69% of males and 64% of females (32% in the uterus). Parasite loads were similar in the testis, vulva, epididymis and vagina and lower in the prostate. Only the parasite load in the vagina was significantly associated with the number of clinical signs. Granulomatous inflammation predominated in all organs, except for the prostate. Only in the testis and epididymis was the inflammatory infiltrate significantly more intense among dogs with a higher parasite load in these organs. The high frequency, detection of active infection and similarity of L. infantum loads in the genital tract of infected males and females suggest the potential of venereal transmission of this parasite by both sexes and of vertical transmission by females in the area studied. Additionally, vertical transmission may be frequent since active L. infantum infection was a common observation in the uterus.

Co-circulation of Toscana virus and Leishmania infantum in a focus of zoonotic visceral leishmaniasis from Central Tunisia

In the Mediterranean basin, sand flies are vectors of Leishmania parasites and phleboviruses affecting humans and animals. In this study, we aimed to investigate phlebovirus and Leishmania parasites circulating in a focus of zoonotic visceral leishmaniasis (ZVL) located in a highly irrigated area within the arid Central Tunisia, known mainly to be endemic for zoonotic cutaenous leishmaniasis (ZCL) caused Leishmania major and transmitted by Phlebotomus papatasi. Sand flies were collected using CDC light traps in the village of Saddaguia, an emergent focus of ZVL located in Central Tunisia during September-October 2014, 2015, and 2016. Pools of live female sand flies were screened for phleboviruses and Leishmania by nested PCR in the polymerase gene and kinetoplast minicircle DNA, respectively. Dead sand flies were identified morphologically to species level. Sand flies of the subgenus Larroussius mainly Phlebotomus perfiliewi, Phlebotomus perniciosus, and Phlebotomus longicuspis were predominant in this ZVL focus compared to P. papatasi. A total of 1932, 1740, and 444 sand flies were tested in 2014, 2015 and 2016, respectively. Pathogen screening performed on 4116 sand flies distributed in 148 pools revealed the presence of Leishmania infantum and Toscana virus. The minimum infection rates of sand flies with TOSV in 2014, 2015, and 2016 were 0.05%, 011%, and 0.22%, respectively. The minimum infection rates of sand flies with L. infantum in 2014, 2015, and 2016 were 0.25%, 012%, and 0.79%, respectively. No L. major was detected during the 3-years investigation in this ZVL focus. Our results showed clearly the endemic co-circulation of TOSV and L. infantum in this emergent ZVL focus. However, no co-infection of TOSV and L. infantum was detected in any of the sand fly pools investigated during the three years period. TOSV was isolated from positive pools in 2015. Phylogenetic analysis showed that the Tunisian strains of TOSV belonged to the sublineage A. Based on the present findings, our results provided strong evidence that TOSV and L. infantum are transmitted by the same predominant sand fly species of the subgenus Larroussius, and subsequently, humans and dogs could be co-infected through co-infected or successive infected bites. Our results showed clearly that the development of irrigation in arid areas contributed significantly to the establishment of stable transmission cycles of L. infantum and TOSV and subsequently to the emergence of a ZVL focus within this arid bio-geographical area characterized by the presence of multiple foci of ZCL located outside the study site. Thus, more studies are needed to better understand the impact of RNA viruses shared by vectors and reservoir hosts of L. infantum on the development of zoonotic visceral leishmaniasis.

Leishmania major degrades murine CXCL1 - An immune evasion strategy

Leishmaniasis is a global health problem with an estimated report of 2 million new cases every year and more than 1 billion people at risk of contracting this disease in endemic areas. The innate immune system plays a central role in controlling L. major infection by initiating a signaling cascade that results in production of pro-inflammatory cytokines and recruitment of both innate and adaptive immune cells. Upon infection with L. major, CXCL1 is produced locally and plays an important role in the recruitment of neutrophils to the site of infection. Herein, we report that L. major specifically targets murine CXCL1 for degradation. The degradation of CXCL1 is not dependent on host factors as L. major can directly degrade recombinant CXCL1 in a cell-free system. Using mass spectrometry, we discovered that the L. major protease cleaves at the C-terminal end of murine CXCL1. Finally, our data suggest that L. major metalloproteases are involved in the direct cleavage and degradation of CXCL1, and a synthetic peptide spanning the CXCL1 cleavage site can be used to inhibit L. major metalloprotease activity. In conclusion, our study has identified an immune evasion strategy employed by L. major to evade innate immune responses in mice, likely reservoirs in the endemic areas, and further highlights that targeting these L. major metalloproteases may be important in controlling infection within the reservoir population and transmittance of the disease.

Our study discovered a highly specific role for L. major metalloprotease in cleaving and degrading murine CXCL1. Indeed, L. major metalloprotease did not cleave murine CXCL2 or human CXCL1, CXCL2 and CXCL8. CXCL1 is a critical chemokine required for neutrophil recruitment to the site of infection; thus, we propose that this metalloprotease may have evolved to evade immune responses specifically in the murine host. We have further identified that the C-terminal end on CXCL1 is targeted for cleavage by the L. major metalloprotease. Finally, this cleavage site information was used to design peptides that are able to inhibit CXCL1 degradation by L. major. Our study highlights an immune evasion strategy utilized by L. major to establish infection within a murine host.

Knowledge and attitudes of Tunisian dog owners regarding leishmaniasis

BACKGROUND

Visceral leishmaniasis is a zoonotic disease of major public health concern in several countries in the world. The local population awareness would improve prevention, early detection and treatment of both human and animal leishmaniasis.

METHODS

The aim of this survey was to assess the knowledge about visceral leishmaniasis in a sample of dog owners visiting the National School of Veterinary Medicine of Sidi Thabet, Tunisia, through a structured questionnaire.

FINDINGS

Two hundred dog owners were interviewed, 87% were men and 47% had higher education level. Ninety four per cent were from neighbouring districts to Ariana, where the National School of Sidi Thabet is located. Out of 200 respondents, 79 confirmed knowing leishmaniasis. The correct answers concerning canine visceral leishmaniasis (CVL) (77%) were significantly higher than those concerning human visceral leishmaniasis (HVL) (23%). Correct answers concerning CVL were given in part by previously diseased dogs' owners. The respondent could not explain what is exactly leishmaniasis, but the majority of questioned persons know that human and dogs are the most important hosts. Forty-four out 79 (56%) of the persons think that mosquitoes or insects are the vectors of leishmaniasis and 63% (53/79) knows that it is a zoonotic disease but 72% (38/53) were not able to define how.

CONCLUSION

Despite the frequent visits to veterinarians for vaccination or other medical issues and their long experience in dog breeding, the sample of dog owners had not enough knowledge and several misconceptions regarding leishmaniasis. Large education programmes should be implemented in Tunisia to improve the knowledge of the Tunisian population, especially dog owners, concerning leishmaniasis.

Retrospective evaluation of vector-borne infections in dogs imported from the Mediterranean region and southeastern Europe (2007-2015)

BACKGROUND

Canine vector-borne infections have gained importance in Germany due to growing tourist traffic and an increased import of dogs from abroad. Endemic regions for pathogens such as Leishmania infantum, Hepatozoon canis, Ehrlichia canis, Anaplasma platys and Dirofilaria spp. are the Mediterranean area and southeastern Europe. Babesia species and Anaplasma phagocytophilum are present all over Europe. The objective of this retrospective study was to evaluate the prevalence of vector-borne infections in dogs imported from defined endemic countries in the Mediterranean area and southeastern Europe.

METHODS

Medical records and laboratory test results of 345 dogs that were imported to Germany from 17 endemic countries and that were presented to the Small Animal Clinic at Freie Universität Berlin between 2007 and 2015 were retrospectively reviewed. A total of 1368 test results from external laboratories were descriptively analysed including 576 and 792 test results of direct and indirect detection methods, respectively.

RESULTS

Overall, 35% (122/345 dogs) were positive for at least one pathogen. Concurrent infections with two to four pathogens were detected in 8% of the dogs (27/345). The positive results were: L. infantum 21% (66/314 dogs; methods: PCR 20/79, IFAT or ELISA 63/308 dogs), E. canis 16% (45/278 dogs; methods: PCR 8/68, IFAT 43/257 dogs), H. canis 11% (3/28 dogs; method: PCR), Babesia spp. 10% (25/251 dogs; methods: Babesia spp. PCR 3/98, B. canis/vogeli IFAT or ELISA 22/214 and B. gibsoni IFAT 0/13 dogs), Dirofilaria spp. 7% (13/178 dogs; methods: D. immitis Ag-ELISA 8/156, Knott's test 7/95, microfilariae PCR 5/23 dogs) and A. platys 5% (1/21 dogs; method: PCR). None of 8 tested dogs were positive in a combined Babesia spp./Hepatozoon spp. PCR test.

CONCLUSIONS

Dogs, which are imported from countries which are endemic for vector-borne infections should be thoroughly tested using direct and indirect detection methods. Potential owners of imported dogs should be informed about the diseases, risks and incubation periods.

Canine Leishmaniasis: An Overview of the Current Status and Strategies for Control

Canine leishmaniasis (CanL) is a vector-borne disease caused by Leishmania infantum and is transmitted by female phlebotomine sand flies primarily between animals and secondarily to humans. The course of infection may be different from one individual dog to another, ranging from spontaneous cure to acute evolution that leads to death, if proper management and therapy are not adopted. A parasitological cure is rarely achieved and clinical recurrences in CanL are frequent. Vaccination associated with the use of topical insecticides is undoubtedly the most effective form of prevention and control of the disease. In order to integrate the most important scientific knowledge of the literature in one objective publication, this review proposes a short overview of the main points of CanL.

Canine leishmaniosis in three consecutive generations of dogs in Czech Republic

Transmission of canine leishmaniosis (CanL) is described in three consecutive generations of female Boxers living in a non-endemic environment in the Czech Republic. Infection of the first generation female likely occurred during a breeding visit to Italy and the dog died with typical clinical signs of the disease but without definitive laboratory diagnosis. The second and third generation offsprings never left the Czech Republic, suffered from clinical CanL confirmed by polymerase chain reaction and serology, and were apparently infected by transplacental transmission. Persistence of CanL in the Czech Republic over 7 years with a suspected origin in an endemic region and progression of infection through subsequent generations in a non-endemic country exemplifies that this disease may establish itself also in areas where no obvious vectors are present.

Vertical transmission of Anaplasma platys and Leishmania infantum in dogs during the first half of gestation

Background

Leishmania infantum is a canine zoonotic vector-borne protozoan pathogen transmitted by phlebotomine sand flies, whereas Anaplasma platys is a bacterium most likely transmitted by ticks. While vertical transmission of L. infantum from pregnant bitches to their offspring has been documented, thus far no studies have explored the possibility of vertical transmission of A. platys in dogs. This study investigated the occurrence of vertical transmission of L. infantum and A. platys in sheltered dogs during the first half of gestation, in an area of southern Italy characterised by a high incidence of infection by both pathogens.

Methods

The study population included 20 bitches (n = 10 pregnant, at 25–35 days of pregnancy; n = 10 non-pregnant), all subjected to ovariohysterectomy, which were examined for the presence of L. infantum and A. platys via cytological screening of bone marrow and whole blood samples. Infection by L. infantum and A. platys was also tested by immunofluorescence antibody test (IFAT) and quantitative real-time PCR (qPCR) targeting both pathogens. Selected tissue samples (n = 210) collected during surgical procedures from bitches and foetuses (n = 20) were assessed for the presence of L. infantum and A. platys by qPCR targeting a fragment of the kinetoplast minicircle DNA (kDNA) and the 16S rRNA gene, respectively.

Results

Leishmania infantum DNA was not amplified from either uteri or ovaries from pregnant bitches or foetal tissue samples, whereas a subset of ovarian (n = 2) and uterine (n = 4) tissue samples from non-pregnant bitches were infected, with parasite loads of up to 3.09 × 10 and 7.51 parasite/PCR reaction, respectively. Conversely, uterine (n = 10) and ovarian (n = 8) tissues from both pregnant and non-pregnant bitches, together with a subset (n = 5) of foetal tissue samples were qPCR positive for A. platys. Leishmania infantum and A. platys nucleic acids were amplified from two uteri from non-pregnant bitches, with parasite loads of up to 2.32 × 10^-3 and 2.05 parasite/per PCR reaction, respectively.

Conclusions

Results from this study suggest that, in contrast to L. infantum, A. platys can be transmitted from pregnant dogs to their offspring during the first half of gestation. This hypothesis remains to be verified, for instance via direct observation of parasites in postpartum foetal tissues.

Occurrence of Leishmania infantum and associated histological alterations in the genital tract and mammary glands of naturally infected dogs

The objectives of this study were to evaluate the occurrence of Leishmania infantum in the male and female genital tract and female mammary glands of dogs and the parasite burden and to identify histological alterations associated with this protozoan. Twenty male and 20 female Leishmania-seropositive dogs with isolation of L. infantum were examined. Tissue samples of the prepuce, glans, epididymis, testes, prostate, vulva, vagina, uterus, uterine tubes, and mammary glands were analyzed by immunohistochemistry and histopathology. For parasitological culture and in situ hybridization, samples were collected from the testis, epididymis, and uterus. Additionally, seminal fluid was aspirated from the epididymis for parasitological culture. In the genital tract, 34 (85 %) dogs, including 18 males and 16 females, were positive for Leishmania. Of these, 27 (79 %) animals were symptomatic. Leishmania was detected in the mammary glands of 13 (65 %) females. L. infantum was isolated for the first time from the seminal fluid and uterus of naturally infected dogs. The parasite burden and intensity of the inflammatory reaction were greater in the prepuce and glans of males and in the vulva and mammary glands of females. In addition to inflammation, testicular degeneration, atrophy, absence of spermatogenesis, and necrosis were observed. Detection of amastigote forms in the mammary gland lumen indicates possible elimination of this parasite in milk. The frequent parasitism observed in the genital tract of infected males and females and the viability of L. infantum in seminal fluid and uterus suggest the possibility of bidirectional venereal and vertical transmission.