Potential Reservoir Hosts Research Articles

Presence of Recombinant Strain of Cucurbit Aphid Borne Yellows Virus in Iran.

Background:Cucurbit aphid-borne yellows virus (CABYV) is among the most important yellowing viruses on cucurbits in Iran. The presence of CABYV has been previously reported from the major cucurbit growing areas in Iran, however, there are few studies concerning the detection of the different strains of this virus in the grower's fields, and especially, there is no report of the weed host plants near crop fields. Objectives: This study was done in order to detect the new strains of the CABYV polerovirus in cucurbits and the weed plants in the Lorestan province, Iran, as an introductory investigation for initiating a program of the breeding for resistance. Material and Methods: During a survey carried out in 2013-2014 in Lorestan province; Iran, 189 cucurbit and 261 weed samples were investigated for the presence of CABYV using RT-PCR. In addition, the phylogeny and nucleotide similarities were discussed on the basis of the partial nucleotide sequence of RNA dependent RNA polymerase (RdRP) gene. Results: The RT-PCR carried out on leaf samples revealed the infection with the CABYV in 43 cucumber and 12 weed samples. RT-PCR using strain specific primers detected the presence of the both common (C) and recombinant (R) strains of CABYV in the tested samples. On the basis of the phylogenetic analyses, the CABYV-C isolates from Iran were clustered into two distinct sub-populations (CI and CII), such that all the weed samples with two sequenced cucumber isolates were clustered in the CI sub-population. Meanwhile, a distinct sub-population of the isolates was clustered in the CABYV-R group showed a shared sequence identity of 97% to a Taiwanese isolate (JQ700306). Conclusions: This study has indicated the incidence of CABYV-R in the Southwest Asia; Iran for the first time. We were also able to show CABYV occurrence in Sysimbrium irio and Citrullus colocynthis from this area of the world. Identification of cucurbit infecting viruses and studying their distribution and potential reservoir hosts are important for developing successful control programs for virus disease management.

Australian penguin ticks screened for novel Borrelia species

Lyme borreliosis (or Lyme Disease) is an emerging threat to human health in the Northern Hemisphere caused by tick-borne bacteria from the Borrelia burgdorferi sensu lato (Bbsl) complex. Seabirds are important reservoir hosts of some members of the Bbsl complex in the Northern Hemisphere, and some evidence suggests this may be true of penguins in the Southern Hemisphere. While the Bbsl complex has not been detected in Australia, a novel Borrelia species (‘Candidatus Borrelia tachyglossi’) was recently sequenced from native ticks (Ixodes holocyclus and Bothriocroton concolor) parasitising echidnas (Tachyglossus aculeatus), suggesting unidentified borreliae may be circulating amongst native wildlife and their ticks. In the present study, we investigated whether ticks parasitising little penguins (Eudyptula novaehollandiae) harbour native or introduced Borrelia bacteria. We chose this penguin species because it is heavily exploited by ticks during the breeding season, lives in close proximity to other potential reservoir hosts (including native wildlife and migratory seabirds), and is known to be infected with other tick-borne pathogens (Babesia). We screened over 230 penguin ticks (Ixodes spp.) from colonies in south-eastern Australia, and found no evidence of Borrelia DNA. The apparent absence or rarity of the bacterium in south-eastern Australia has important implications for identifying potential tick-borne pathogens in an understudied region.

Natural infection of Ctenodactylus gundi by Leishmania major in Tunisia

Incriminating new rodent species, as reservoir hosts of Leishmania parasites is crucial for understanding the transmission cycle of cutaneous leishmaniasis in Tunisia. Ctenodactylus (C.) gundi was previously described as extremely abundant in all Tunisian Leishmania (L.) tropica foci in south Tunisia besides its presence in L. major endemic area. The aim of this study was to detect Leishmania species parasites among C. gundi in two endemic regions in Tunisia: Sidi Bouzid and Tataouine.Total DNA was isolated from the spleens and the livers of 92C. gundi. Leishmaniasis clinical manifestations were detected among 11 rodents (12%). Leishmania parasites were detected in 30 (32.6%) rodents using direct exam method. Leishmania DNA was detected in 40 (43.5%) C. gundi by combining results among spleens and livers using ITS1-PCR. Positive samples were confirmed to be L. major except for only one specimen which was L. tropica.These results demonstrated, for the first time, the high natural infection rate of C. gundi with L. major parasites in Tunisia. Hence, C. gundi should be considered as potential reservoir host of Leishmania parasites causing cutaneous leishmaniasis in Tunisia.

Serological and PCR investigation of Yersinia pestis in potential reservoir hosts from a plague outbreak focus in Zambia

BackgroundPlague is a bacterial zoonotic disease, caused by Yersinia pestis. Rodents are the natural hosts with fleas as the vehicle of disease transmission. Domestic and wild dogs and cats have also been identified as possible disease hosts. In Zambia, plague outbreaks have been reported in the Southern and Eastern regions in the last 20 years. Based on these observations, Y. pestis could possibly be endemically present in the area.MethodsTo substantiate such possibility, sera samples were collected from rodents, shrews, dogs and cats for detection of antibodies against Fraction 1 gene (Fra1) of Y. pestis while organs from rodents and shrews, and fleas from both dogs and rodents were collected to investigate plasminogen activator gene (pla gene) of Y. pestis using ELISA and PCR respectively.ResultsA total of 369 blood samples were collected from domestic carnivores, shrews and domestic and peri-domestic rodents while 199 organs were collected from the rodents and shrews. Blood samples were tested for antibodies against Fra1 antigen using ELISA and 3% (5/165) (95% CI 0.99–6.93%) dogs were positive while all cats were negative. Of 199 sera from rodents and shrews, 12.6% (95% CI 8.30–17.98%) were positive for antibodies against Fra1 using anti-rat IgG secondary antibody while using anti-mouse IgG secondary antibody, 17.6% (95% CI 12.57–23.60%) were positive. PCR was run on the organs and 2.5% (95% CI 0.82–5.77%) were positive for plasminogen activator gene of Y. pestis and the amplicons were sequenced and showed 99% identity with Y. pestis reference sequences. All 82 fleas collected from animals subjected to PCR, were negative for pla gene. The specific rat-flea and dog-flea indices were 0.19 and 0.27 respectively, which were lower than the level required to enhance chances of the disease outbreak.ConclusionsWe concluded that plague was still endemic in the area and the disease may infect human beings if contact is enhanced between reservoir hosts and flea vectors. The lower specific rodent-flea Indices and absence of Y. pestis in the potential vectors were considered to be partly responsible for the current absence of plague outbreaks despite its presence in the sylvatic cycle.

Isolation of the Lyme Disease Spirochete Borrelia mayonii From Naturally Infected Rodents in Minnesota.

Borrelia mayonii is a newly described member of the Borrelia burgdorferi sensu lato complex that is vectored by the black-legged tick (Ixodes scapularis Say) and a cause of Lyme disease in Minnesota and Wisconsin. Vertebrate reservoir hosts involved in the enzootic maintenance of B. mayonii have not yet been identified. Here, we describe the first isolation of B. mayonii from naturally infected white-footed mice (Peromyscus leucopus Rafinesque) and an American red squirrel (Tamiasciurus hudsonicus Erxleben) from Minnesota, thus implicating these species as potential reservoir hosts for this newly described spirochete.

Evidence of African horse sickness virus infection of Equus zebra hartmannae in the south-western Khomas Region, Namibia.

Equine mortalities suspected to be due to African horse sickness (AHS) were reported from the arid Khomas Region, Namibia, in 2008. The area was previously considered a localized AHS-free area. Hartmann's mountain zebra (Equus zebra hartmannae), a potential but unconfirmed reservoir host of African horse sickness virus (AHSV), occurs in the region. Between 2009 and 2010 serum, blood and tissue samples from 31 culled E.z.hartmannae were analysed by reverse transcription-polymerase chain reaction(RT-PCR) (n=31) and enzyme-linked immunosorbent assay (ELISA) (n=18) to determine the presence of AHSV and/or antibodies against AHSV. The presence of antibodies against AHSV was demonstrated in all 18 samples assayed, and AHSV double stranded RNA was detected in 26% of the animals. This is evidence that E.z.hartmannae can become infected with AHSV.

Natural infection of Nesokia indica with Leishmania major and Leishmania infantum parasites in Damghan city, Northern Iran

Various species of rodents are proven reservoir hosts of zoonotic cutaneous leishmaniasis in different provinces of Iran and potential reservoir hosts of zoonotic visceral leishmaniasis. Therefore, this study was conducted to determine the leishmanial infection of rodents in Damghan city from April to September, 2015. Sum of 100 rodents of three species; Nesokia indica (95), Mus musculus (3), and Microtus socialis (2), were trapped alive and their tissue samples were examined using parasitological and molecular (nested-PCR) methods. A total of 71% (71/100) of examined rodents were parasitological positive for Leishmania spp. amastigotes. The highest rate (72.6%; 69/95) of infection was related to the N. indica species. The microscopic observations showed that 42% of ear samples were positive. Additionally, 12% of rodents with negative ear result were positive in liver. 16 out of 41 (39%) parasitological positive samples, belonging to the N. indica, were shown molecularly positive. Of which, 15 were L. major (13 of ear and 2 of spleen samples) and one of spleen samples was L. infantum. This is the first report of N. indica natural infection with L. infantum parasite. To understand the role of this rodent as reservoir host of L. infantum, extant ecological and epidemiological studies are needed.

European Aedes albopictus and Culex pipiens Are Competent Vectors for Japanese Encephalitis Virus.

BackgroundJapanese encephalitis virus (JEV) is the causative agent of Japanese encephalitis, the leading cause of viral encephalitis in Asia. JEV transmission cycle involves mosquitoes and vertebrate hosts. The detection of JEV RNA in a pool of Culex pipiens caught in 2010 in Italy raised the concern of a putative emergence of the virus in Europe. We aimed to study the vector competence of European mosquito populations, such as Cx. pipiens and Aedes albopictus for JEV genotypes 3 and 5.FindingsAfter oral feeding on an infectious blood meal, mosquitoes were dissected at various times post-virus exposure. We found that the peak for JEV infection and transmission was between 11 and 13 days post-virus exposure. We observed a faster dissemination of both JEV genotypes in Ae. albopictus mosquitoes, when compared with Cx. pipiens mosquitoes. We also dissected salivary glands and collected saliva from infected mosquitoes and showed that Ae. albopictus mosquitoes transmitted JEV earlier than Cx. pipiens. The virus collected from Ae. albopictus and Cx. pipiens saliva was competent at causing pathogenesis in a mouse model for JEV infection. Using this model, we found that mosquito saliva or salivary glands did not enhance the severity of the disease.ConclusionsIn this study, we demonstrated that European populations of Ae. albopictus and Cx. pipiens were efficient vectors for JEV transmission. Susceptible vertebrate species that develop high viremia are an obligatory part of the JEV transmission cycle. This study highlights the need to investigate the susceptibility of potential JEV reservoir hosts in Europe, notably amongst swine populations and local water birds.

Pathological vicissitudes and oxidative stress enzyme responses in mice experimentally infected with reptarenavirus (isolate UPM/MY01).

Boid inclusion body disease (BIBD) is a viral disease of boid snakes believed to be caused by reptarenavirus belonging to the family Arenaviridae. Unlike most mammalian arenaviruses, the reservoir host for reptarenavirus is still unknown. In this study, the pathological responses were evaluated in a mouse model for a period of 28 days. Blood and tissue samples (lung, liver, spleen, heart, kidney and brain) were collected for evaluation of hematology, biochemistry, histopathology and oxidative enzyme levels at six time points (1, 3, 7, 14, 21 and 28 days), after viral infection (2.0×106pfu/mL) in the infected and normal saline in the control groups. An initial increase (p<0.05) in white blood cell (WBC), neutrophil and lymphocyte counts were observed in the infected group at day 3 post infection, and a decline (p<0.05) on day 7 and 4 post infection. Significant (p<0.05) increases in alanine transaminase (ALT), aspartate transaminase (AST), creatinine, total protein and globulin levels were also observed in the infected group. An increased (p<0.05) level of hydrogen peroxide, total antioxidant capacity (TAC), superoxide dismutase (SOD) activity and catalase activity (CAT) were frequently observed on different days in the infected group. The MDA activity was increased (p<0.05) in the infected group on day 7 and 14. Histopathological changes observed in the liver, kidney, spleen, brain and lungs were mainly associated with degeneration, necrosis and infiltration of lymphocytes. Viral counts were low on days 7 and 14 but surged in both the liver and spleen on day 21 and 28. This study has shown that reptarenavirus replicates in mammalian host and induces oxidative stress. Furthermore, the resultant hematobiochemical and histopathological changes observed in infected mice were similar to what has been reported in mammarenavirus infections. This suggests that rodents may serve as potential reservoir hosts for reptarenavirus.

Ecology of phlebotomine sandflies and putative reservoir hosts of leishmaniasis in a border area in Northeastern Mexico: implications for the risk of transmission of Leishmania mexicana in Mexico and the USA.

Leishmaniases are a group of important diseases transmitted to humans through the bite of sandfly vectors. Several forms of leishmaniases are endemic in Mexico and especially in the Southeast region. In the Northeastern region, however, there have only been isolated reports of cases and scanty records of sandfly vectors. The main objective of this study was to analyze the diversity of sandflies and potential reservoir hosts of Leishmania spp. in the states of Nuevo León and Tamaulipas. Species richness and abundances of sandflies and rodents were recorded. A fraction of the caught sandflies was analyzed by PCR to detect Leishmania spp. Tissues from captured rodents were also screened for infection. Ecological Niche Models (ENMs) were computed for species of rodent and their association with crop-growing areas. We found 13 species of sandflies, several of which are first records for this region. Medically important species such as Lutzomyia anthophora, Lutzomyia diabolica, Lutzomyia cruciata, and Lutzomyia shannoni were documented. Leishmania spp. infection was not detected in sandflies. Nine species of rodents were recorded, and Leishmania (Leishmania) mexicana infection was found in four species of Peromyscus and Sigmodon. ENMs showed that potential distribution of rodent pest species overlaps with allocated crop areas. This shows that Leishmania (L.) mexicana infection is present in the Northeastern region of Mexico, and that previously unrecorded sandfly species occur in the same areas. These findings suggest a potential risk of transmission of Leishmania (L.) mexicana.

Epidemiological Investigation of Asymptomatic Dogs with Leishmania Infection in Southwestern China Where Visceral Leishmaniasis is Intractable.

Heishui county, located in northwest Sichuan province, southwestern China, is an endemic area of zoonotic visceral leishmaniasis (VL) and is the most intractable area. VL is never destroyed in it. Asymptomatic dogs (Leishmania parasites have been diagnosed but clinically healthy) are considered to be a potential reservoir host in zoonotic VL area, and most can lead to infection of individuals, that is a new challenge for controlling VL in humans. The present study aimed to assess the Leishmania infection rate of asymptomatic dogs in Heishui county. Total 105 asymptomatic domestic dogs were gathered from 4 districts in Heishui county to investigate the infection rate with serological and molecular methods based on ELISA and kinetoplast minicircle DNA(kDNA) PCR, respectively. Out of 105 dogs, 44 (41.9%) were positive by more than 1 method; 21 (20.0%) were positive by ELISA, and 30 (28.6%) were positive by kDNA-PCR. Our study showed that Leishmania infection of domestic dogs which is clinically healthy is prevalent in the studied district, and the asymptomatic dogs infected by Leishmania may be the primary reason for the prevalence of visceral leishmaniasis in the area.

Reservoir-host amplification of disease impact in an endangered amphibian.

Emerging wildlife pathogens are an increasing threat to biodiversity. One of the most serious wildlife diseases is chytridiomycosis, caused by the fungal pathogen, Batrachochytrium dendrobatidis (Bd), which has been documented in over 500 amphibian species. Amphibians vary greatly in their susceptibility to Bd; some species tolerate infection, whereas others experience rapid mortality. Reservoir hosts-species that carry infection while maintaining high abundance but are rarely killed by disease-can increase extinction risk in highly susceptible, sympatric species. However, whether reservoir hosts amplify Bd in declining amphibian species has not been examined. We investigated the role of reservoir hosts in the decline of the threatened northern corroboree frog (Pseudophryne pengilleyi) in an amphibian community in southeastern Australia. In the laboratory, we characterized the response of a potential reservoir host, the (nondeclining) common eastern froglet (Crinia signifera), to Bd infection. In the field, we conducted frog abundance surveys and Bd sampling for both P. pengilleyi and C. signifera. We built multinomial logistic regression models to test whether Crinia signifera and environmental factors were associated with P. pengilleyi decline. C. signifera was a reservoir host for Bd. In the laboratory, many individuals maintained intense infections (>1000 zoospore equivalents) over 12 weeks without mortality, and 79% of individuals sampled in the wild also carried infections. The presence of C. signifera at a site was strongly associated with increased Bd prevalence in sympatric P. pengilleyi. Consistent with disease amplification by a reservoir host, P. pengilleyi declined at sites with high C. signifera abundance. Our results suggest that when reservoir hosts are present, population declines of susceptible species may continue long after the initial emergence of Bd, highlighting an urgent need to assess extinction risk in remnant populations of other declined amphibian species.

Strategies for Trypanosoma brucei gambiense elimination.

Strategies for Trypanosoma brucei gambiense elimination.

Molecular evidence for Toxoplasma gondii in feeding and questing Ixodes ricinus ticks

The aim of the present study was to detect Toxoplasma gondii in ticks collected from ponies and field vegetation and to determine the role of Shetland ponies as a potential reservoir host for T. gondii. A total of 1737 feeding Ixodes ricinus collected from 49 horses and 371 questing ticks were tested by PCR and sequencing for the presence and genotyping of T. gondii. All ticks were examined in a previous study to detect and identify pathogenic bacterial species. The aim of this study was also to detect co-infection of ticks with these bacteria and T. gondii. Genotyping of the sequenced B1 gene revealed that detected T. gondii strains represented genotype I, which is pathogenic for humans. T. gondii genotype I was detected in 4.5% of all I. ricinus, including in 2.99% of feeding ticks and in 10.24% of questing ticks; this difference was statistically significant. Thus, the above results indicate that ponies probably are not an essential host for the detected sporozoan. Infections with more than one pathogenic species were rare and involved mostly T. gondii and Borrelia burgdorferi sensu lato. Our results confirmed the presence of T. gondii in I. ricinus and showed a new geographical habitat of T. gondii occurring in I. ricinus ticks in Poland.

Rickettsia spp. in small mammals and their parasitizing ectoparasites from Saxony, Germany

Rickettsiae are emerging pathogens causing various types of spotted fever and typhus and are mostly transmitted by arthropods to humans and animals. In order to investigate the distribution of Rickettsiae of the spotted fever group (SFG) in small mammals as potential reservoirs and in fleas and ticks from these animals as potential vectors, a total of 91 small mammals (seven species) were captured and their ectoparasites were collected at seven sites around Leipzig, Saxony, Germany, in 2010 and 2011. Altogether, 91 skin samples, 125 fleas (five species) and 363 ticks (four species) were investigated for DNA of Rickettsia spp. with a real-time PCR targeting the gltA gene. A total of 26 (28.6%) rodents, 5 (3.9%) fleas and 151 (41.6%) ticks were positive for Rickettsia spp. by real-time PCR. Altogether 42 positive tick-, and all positive small mammal- and flea-samples were further determined to Rickettsia species level with a conventional PCR targeting the ompB gene followed by sequencing. Sequencing of 14 positive rodent samples revealed R. helvetica (n=12) and R. raoultii (n=2). Three Rickettsia spp. were detected in ticks: Rickettsia raoultii (59.6%), R. monacensis (4.8%) and R. helvetica (33.3%). In total 85.6% of Dermacentor reticulatus ticks and 20.4% of Ixodes ricinus ticks were positive. Rickettsia raoultii was found in 4 of the 5 positive fleas. To our knowledge this is the first detection of R. raoultii in Myodes glareolus and of R. helvetica in Apodemus agrarius from Germany. The high prevalence of R. helvetica in small mammals suggests that they may play an important role as potential natural reservoir hosts. The high prevalence in engorged I. ricinus for R. helvetica and in D. reticulatus ticks for R. raoultii, mostly deriving from uninfected mammals, leads to the conclusion that those tick species may serve as vectors for those Rickettsia spp. Detection of R. raoultii in fleas, parasitizing on their small mammal hosts, may indicate accidental uptake during feeding on hosts with bacteraemia rather than an active involvement of fleas in the transmission cycle of this Rickettsia species.

Adaptive evolution of virus-sensing toll-like receptor 8 in bats.

Recently, bats have gained attention as potential reservoir hosts for emerging zoonotic single-stranded (ssRNA) viruses that may prove fatal for humans and other mammals. It has been hypothesized that some features of their innate immune system may enable bats to trigger an efficient early immune response. Toll-like receptors (TLRs) represent a first line defense within the innate immune system and lie directly at the host–pathogen interface in targeting specific microbe-molecular patterns. However, the direction and strength of selection acting on TLRs are largely unknown for bats. Here, we studied the selection on viral ssRNA sensing TLR8 based on sequence data of 21 bat species. The major part (63 %) of the TLR8 gene evolved under purifying selection, likely due to functional constraints. We also found evidence for persistent positive selection acting on specific amino acid sites (7 %), especially when compared to viral TLR evolution of other mammals. All of these putatively positively selected codons were located in the ligand-binding ectodomain, some coincidenced or were in close proximity to functional sites, as suggested by the crystallographic structure of the human TLR8. This might contribute to the inter-species variation in the ability to recognize molecular patterns of viruses. TLR8 evolution within bats revealed that branches leading to ancestral and recent lineages evolved under episodic positive selection, indicating selective selection pressures in restricted bat lineages. Altogether, we found that the TLR8 displays extensive sequence variation within bats and that unique features separate them from humans and other mammals.Electronic supplementary materialThe online version of this article (doi:10.1007/s00251-016-0940-z) contains supplementary material, which is available to authorized users.

Differential associations of Borrelia species with European badgers (Meles meles) and raccoon dogs (Nyctereutes procyonoides) in western Poland

European badgers and raccoon dogs and their associated ticks and lice were assayed for the presence of Lyme borreliosis and relapsing fever-group spirochete DNA in western Poland. Analyses of blood, ear-biopsy and liver samples revealed that 25% of 28 raccoon dogs and 12% of 34 badgers were PCR positive for borreliae. Borrelia garinii was the dominant species in raccoon dogs (62.5%), followed by B. afzelii (25%) and B. valaisiana (12.5%). PCR-positive badgers were infected only with B. afzelii. A total of 351 attached ticks was recovered from 23 (82%) of the raccoon dogs and 13 (38%) of the badgers. Using a nested PCR targeting the ITS2 fragments of Ixodes DNA, four Ixodes species were identified: I. ricinus, I. canisuga, I. hexagonus, and one provisionally named I. cf. kaiseri. Ixodes canisuga and I. ricinus prevailed on both host species. The highest infection prevalence was detected in I. ricinus, followed by I. canisuga and I. cf. kaiseri. Borrelia garinii and B. afzelii accounted for 61.6% and 30.1% of the infections detected in all PCR-positive ticks, respectively. Four other Borrelia species (B. burgdorferi sensu stricto, B. valaisiana, B. lusitaniae and B. miyamotoi) were detected only in I. ricinus from raccoon dogs. Moreover, Borrelia DNA, mostly B. garinii, was detected in 57 (81.4%) of 70 Trichodectes melis lice derived from 12 badgers. The detection of B. afzelii in one-half of PCR-positive biopsies reconfirms previous associations of this species with mammalian hosts, whereas the high prevalence of B. garinii in feeding lice and I. ricinus ticks (including larvae) demonstrates that both carnivores serve as hosts for B. garinii. The lack of B. garinii DNA in the tissues of badgers versus its prevalence in raccoon-dog biopsies, however, incriminates only the latter carnivore as a potential reservoir host.

F. novicida-Infected A. castellanii Does Not Enhance Bacterial Virulence in Mice.

Francisella tularensis is a facultative intracellular bacterium that causes tularemia in humans and animals. Epidemiology of tularemia worldwide is often associated with water-borne transmission, which includes mosquitoes and amoebae as the potential host reservoirs of the bacteria in water environment. In vitro studies showed intracellular replication of F. tularensis within Acanthamoeba castellanii and Hartmanella vermiformis cells. While infection of amoeba by Legionella pneumophila has been shown to enhance infectivity of L. pneumophila the role of F. tularensis-infected protozoa in the pathogenesis of tularemia is not known. We used 6 h coculture of A. castellanii and F. novicida for investigation of the effect of inhaled amoeba on the pathogenesis of tularemia on in vivo model. Balb/c mice were infected intratracheally with F. novicida or with F. novicida-infected A. castellanii. Surprisingly, infection with F. novicida-infected A. castellanii did not lead to bronchopneumonia in Balb/c mice, and Francisella did not disseminate into the liver and spleen. Upon inhalation, F. novicida infects a variety of host cells, though neutrophils are the predominant cells early during infection in the lung infiltrates of pulmonary tularemia. The numbers of neutrophils in the lungs of Balb/c mice were significantly lower in the infection of mice with F. novicida-infected A. castellanii in comparison to group of mice infected only with F. novicida. These results demonstrate that following inoculation of mice with F. novicida-infected A. castellanii, mice did not develop tularemia.

Red fox (Vulpes vulpes) as a potential reservoir host of cardiorespiratory parasites in Bosnia and Herzegovina

Red fox (Vulpes vulpes) is considered as reservoir of different cardiorespiratory parasites of veterinary and medical importance. Since data on cardiorespiratory parasites in foxes in Bosnia and Herzegovina are still lacking, the aims of the present study were to (i) investigate the prevalence and geographical distribution of these parasites, (ii) determine genetic diversity of detected parasite species, and (iii) to estimate the role of foxes in the transmission cycle to companion animals and humans. Four species, morphologically and molecularly identified as Eucoleus boehmi (64.6%; 51/79), Eucoleus aerophilus (69.7%; 154/221), Crenosoma vulpis (45.7%; 101/221) and Linguatula serrata (1.3%; 1/79) were retrieved from nasal cavity and lungs in 184 (83.3%) animals. The occurrence of heartworms, Angiostrongylus vasorum and Dirofilaria immitis was not detected by necropsy or PCR. Furthermore, three distinct haplotypes of E. aerophilus (I, III, XV) and two of C. vulpis (I, II) previously reported in pet animals and wild carnivores were confirmed in this study. A new haplotype of C. vulpis (designated as haplotype V) was also identified based on 12S rRNA gene for the first time. The present study indicates a high prevalence and wide distribution of nasal and lung nematodes in fox population in Bosnia and Herzegovina, and supports the existence of transmission patterns between wildlife and pet animals.

The impact of compartmentalised housing on direct encephalomyocarditis virus (EMCV) transmission among pigs; insight from a model

Although generally considered a rodent virus, pigs sometimes were suggested a potential reservoir host for encephalomyocarditis virus (EMCV), implying pig-to-pig transmission can cause major outbreaks in a pig population (basic reproduction ratio, R0>1). An earlier experimental study on EMCV transmission among pigs was inconclusive in this respect (R0≈1.24; CI 0.4–4.4). In this study we used a simulation model to extrapolate the experimental results to commercial, compartmentalised pig housings and tested to what extend contacts between pigs in different pens needed to be reduced in order to prevent major outbreaks in a compartment following a single introduction. The final size of simulated outbreaks was measured and the probability to observe outbreaks that affected at least 50 or 80% of the pens was calculated. Simulation scenarios compare one homogeneously mixing compartment (no fence) to epidemiological theory and an increasing effect of fencing on the pig-to-pig transmission between pigs in neighbouring pens. For any R0<1.24 the probability to observe outbreaks affecting more than 50% of the pens remained below 10% if compartmentalisation was introduced leaving per capita transmission rate unchanged. If fences also reduced contact transmission the probability to observe major outbreaks was below 50% for any R0<2.7. Only for R0>4, major outbreaks occurred with more than 50% chance even if only minimal contact between adjacent pens was allowed. In conclusion the results suggested that in a compartmentalised pig housing one single EMCV introduction is unlikely to cause a major outbreak by direct pig-to-pig transmission alone. Other mechanisms e.g. multiple introductions from a rodent reservoir may be required for large outbreaks to occur.