[First report on Leptospira interrogans in the sigmodontine rodent Scapteromys aquaticusPrimeiro relato da presença de Leptospira interrogans em roedores sigmodontíneos Scapteromys aquaticus]. / Primer informe de Leptospira interrogans en el roedor sigmodontino Scapteromys aquaticus.

Leptospirosis is a globally distributed zoonosis that can be transmitted through direct or indirect contact with the urine or tissues of infected animals. In Argentina, leptospirosis is endemic in the province of Santa Fe and epidemic outbreaks occur during floods. However, very little is known about the role that wild rodents play in the spread of the disease in Argentina. The objective of this study was to identify the host species of pathogenic Leptospira among rodents in a riverine settlement in the province of Santa Fe.We conducted a trapping session in October 2015. Kidneys of the captured animals were analyzed by real-time PCR for the LipL32 gene of pathogenic Leptospira. Animals that were positive were subjected to microscopic agglutination test (MAT) and molecular typing by amplification of the 16S rRNA gene and two multilocus sequence typing (MLST) schemes.A total of 37 rodents of the species Akodon azarae, Cavia aperea, Oligoryzomys flavescens, Rattus rattus, and Scapteromys aquaticus were captured. Real-time PCR found one male Scapteromys aquaticus that was positive. The serum of this individual and of the rest of the S. aquaticus captured (n = 18) were analyzed by MAT and were non-reactive for the 10 serovars tested. Amplification of the 16S rRNA gene identified the infective species as Leptospira interrogans, while amplification could not be obtained for the two MLST schemes.The findings of this study contribute new information concerning the presence of pathogenic Leptospira in wild rodents, which is relevant in this region because the species is widely distributed in swampy and flood-prone environments of South America.

A leptospirose é uma doença zoonótica de distribuição mundial transmitida pelo contato direto ou indireto com a urina ou os tecidos de animais infectados. Na Argentina, a leptospirose é endêmica na Província de Santa Fé com surtos epidêmicos ocorrendo com as enchentes. Sabe-se pouco sobre o papel dos roedores silvestres na propagação da doença no país. O objetivo deste estudo foi identificar as espécies hospedeiras de leptospiras patogênicas em roedores encontrados em um núcleo de povoamento ribeirinho na Província de Santa Fé.A amostragem dos roedores foi feita no mês de outubro de 2015. Os tecidos dos rins dos animais capturados foram analisados com a técnica de reação em cadeia da polimerase em tempo real (PCR-RT) quanto à presença do gene LipL32 de leptospiras patógenas. Para os animais com resultados positivos, foi realizado o teste de microaglutinação (MAT) e tipagem molecular baseada na amplificação do gene 16S rRNA e dois esquemas de tipagem por sequenciamento de locos múltiplos (MLST).Ao todo, foram capturados 37 roedores das espécies Akodon azarae, Cavia aperea, Oligoryzomys flavescens, Rattus e Scapteromys aquaticus. O ensaio de PCR-RT foi positivo em um roedor macho da espécie Scapteromys aquaticus. Os soros deste animal e dos outros S. aquaticus capturados (n = 18) foram analisados com o MAT e os resultados foram não reagentes para os 10 sorovares testados. A amplificação do gene 16S rRNA permitiu identificar a espécie infetante como sendo Leptospira interrogans e não houve amplificação nos dois esquemas de MLST.O achado deste estudo fornece um novo dado quanto à presença de leptospiras patogênicas em roedores silvestres, importante para esta área por se tratar de uma espécie de ampla distribuição em terras pantanosas e inundáveis da América do Sul.

[Interleukin-2 for the treatment of cows with malignant catarrhal fever]. / Behandlung von Rindern mit Bösartigem Katarrhalfieber mit Interleukin-2.

The goal of this study was to investigate whether administration of interleukin-2 (IL-2) would improve the outcome of cows with malignant catarrhal fever (MCF). The study population consisted of ten healthy control cows and 22 cows with MCF. Nineteen cows with MCF and all of the controls were treated with either 2'500 U IL-2 or 25'000 U IL-2, administered intravenously. Three cows with MCF were not treated with IL-2 (MCF controls). All of the cows with MCF received danofloxacin, flunixin meglumine and intravenous fluid therapy. Blood samples for haematological and biochemical evaluation were collected once daily for six days in all cows. Of the 19 cows treated with IL-2, 13 were eutha nized because of deterioration. All cows with MCF that did not receive IL-2 died. The clinical condition of six cows treated with 2'500 U IL-2 gradually improved. Sur viving cows had significantly higher total leukocyte counts than cows that died or were euthanized. The main reason for leukopenia in non-surviving vs. surviv ing cows was persistent lymphopenia. Use of the lower IL-2 dose was associated with clinical recovery in some cows and this treatment might therefore be considered in valuable cows, provided that the lymphocyte count is within the reference interval.

When is a parasite not a parasite? Effects of larval tick burdens on white-footed mouse survival.

Many animal species can carry considerable burdens of ectoparasites: parasites living on the outside of a host's body. Ectoparasite infestation can decrease host survival, but the magnitude and even direction of survival effects can vary depending on the type of ectoparasite and the nature and duration of the association. When ectoparasites also serve as vectors of pathogens, the effects of ectoparasite infestation on host survival have the potential to alter disease dynamics by regulating host populations and stabilizing transmission. We quantified the impact of larval Ixodes scapularis tick burdens on both within-season and overwinter survival of white-footed mice (Peromyscus leucopus) using a hierarchical Bayesian capture-mark-recapture model. I. scapularis and P. leucopus are, respectively, vectors and competent reservoirs for the causative agents of Lyme disease, anaplasmosis, and babesiosis. Using a data set of 5587 individual mouse capture histories over sixteen years, we found little evidence for any effect of tick burdens on either within-season or overwinter mouse survival probabilities. In male mice, tick burdens were positively correlated with within-season survival probabilities. Mean maximum tick burdens were also positively correlated with population rates of change during the concurrent breeding season. The apparent indifference of mice to high tick burdens may contribute to their effectiveness as reservoir hosts for several human zoonotic pathogens.

Seroprevalence of Leptospira antibodies in dogs and cats from Santa Fe, a city in East-Central Argentina endemic for leptospirosis.

This study examines household pets as potential epidemiological links between environments contaminated with pathogenic leptospires and humans in Santa Fe, Argentina. The aims of our study were: (a) to characterize the habits and exposure to environmental sources of leptospirosis in the population of dogs and cats attending to municipal spay and neutering campaigns in Santa Fe, Argentina, (b) to assess the seroprevalence of anti-Leptospira antibodies in asymptomatic dogs and cats, (c) to evaluate factors that could increase seropositivity, and (d) to identify spatial clusters of seropositive dogs and cats in the capital city of Santa Fe. From May to November 2022, a cross-sectional serosurvey was conducted during municipal spaying/neutering campaigns. Eligible household dogs and cats were over 6 months old, apparently healthy, and not vaccinated against leptospirosis in the past 6 months. We used microagglutination test (MAT) to assess anti-Leptospira antibodies using a panel of 10 reference strains. We used generalized linear mixed effects models (GLMM) to examine individual and census tract-level risk factors for seropositivity, and local Moran's I statistic for spatial clusters. Results showed higher leptospiral antibody prevalence in dogs (18.2 %) than cats (3.6 %, p = 0.002). Dogs with street access had higher likelihood of being seropositive (OR: 3.8, 95 % CI: 1.2; 11.9), and areas with chronic poverty showed an elevated risk of presenting seropositive animals (RR: 4.0, 95 % CI: 1.1; 14.4). Spatial analysis didn't reveal significant seropositivity clusters among census tracts. These findings shed light on widespread Leptospira seropositivity in pets in this endemic region. Understanding seroprevalence and risk factors can guide public and veterinary health strategies, emphasizing increased leptospirosis vaccination for dogs in vulnerable areas and promoting responsible pet care.

Intra-phylum and inter-phyla associations among gastrointestinal parasites in two wild mammal species.

A growing body of literature reveals that the interactions among the parasite community may be strong and significant for parasite dynamics. There may be inter-specific antagonistic interactions as a result of competition and cross-effective immune response, or synergistic interactions where infection by one parasite is facilitated by another one, either by an impoverishment of the host's defenses, parasite-induced selective immunosuppression, or trade-offs within the immune system. The nature of these interactions may depend on how related are the parasite species involved. Here we explored the presence of associations among gastrointestinal parasites (coccidia and helminths) in natural populations of two wild mammal species, the capybara (Hydrochoerus hydrochaeris) and the guanaco (Lama guanicoe). The associations explored were between the oocyst outputs of a selected Eimeria species and the other coccidia of that parasite community, and between Eimeria spp. and the predominant nematodes. The statistical analysis included adjustment for potential confounders or effect modifiers. In guanacos, the prevailing interactions were synergistic among the coccidia and between coccidia and nematodes (Nematodirus spp.). However, in capybaras, the interaction between nematodes (Viannaiidae) and Eimeria spp. depended on environmental and host factors. The relationship was positive in some circumstances (depending on season, year, sex, or animal size), but it appeared to become antagonistic under different scenarios. These antagonist interactions did not follow a particular seasonal pattern (they occurred in autumn, spring, and summer), but they were predominantly found in females (when they depended on sex) or in 2010 and 2011 (when they depended on the sampling year). These results suggest that the relationship between coccidia and nematodes in capybaras may be context dependent. We propose that the context-dependent immune investment documented in capybaras may be the cause of these varying interactions.

[Biphasic mesothelioma in a Swiss Braunvieh cow: clinical, histological, immunohistochemical and electron microscopical findings]. / Biphasisches Mesotheliom bei einer Braunviehkuh: Klinische, histomorphologische, immunhistochemische und elektronenmikroskopische Befunde.

A 10-year-old Swiss Braunvieh cow near term was referred to our clinic because of severe abdominal distension, which caused loss of demarcation between the udder and ventral abdominal wall. Ultrasonographic examination revealed marked ascites and multiple echogenic nodules in the greater omentum. Based on the findings, non-inflammatory ascites attributable to neoplasia was diagnosed. Rupture of the prepubic tendon from the pubic symphysis was also suspected. Because of a grave prognosis, parturition was induced and a live calf was delivered. The cow was euthanized and a postmortem examination was carried out. The abdominal cavity contained 248.5 litres of clear fluid. The greater omentum was thickened and oedematous and regionally contained fluid-filled cystic structures, which varied in size with a maximum diameter of 10 centimetres. Based on the histological, immunohistochemical and electron microscopical findings, biphasic mesothelioma with cyst formation affecting the entire abdominal cavity was diagnosed.

Determining the spatial distribution of environmental and socio-economic suitability for human leptospirosis in the face of limited epidemiological data.

BACKGROUND: Leptospirosis is among the leading zoonotic causes of morbidity and mortality worldwide. Knowledge about spatial patterns of diseases and their underlying processes have the potential to guide intervention efforts. However, leptospirosis is often an underreported and misdiagnosed disease and consequently, spatial patterns of the disease remain unclear. In the absence of accurate epidemiological data in the urban agglomeration of Santa Fe, we used a knowledge-based index and cluster analysis to identify spatial patterns of environmental and socioeconomic suitability for the disease and potential underlying processes that shape them. METHODS: We geocoded human leptospirosis cases derived from the Argentinian surveillance system during the period 2010 to 2019. Environmental and socioeconomic databases were obtained from satellite images and publicly available platforms on the web. Two sets of human leptospirosis determinants were considered according to the level of their support by the literature and expert knowledge. We used the Zonation algorithm to build a knowledge-based index and a clustering approach to identify distinct potential sets of determinants. Spatial similarity and correlations between index, clusters, and incidence rates were evaluated. RESULTS: We were able to geocode 56.36% of the human leptospirosis cases reported in the national epidemiological database. The knowledge-based index showed the suitability for human leptospirosis in the UA Santa Fe increased from downtown areas of the largest cities towards peri-urban and suburban areas. Cluster analysis revealed downtown areas were characterized by higher levels of socioeconomic conditions. Peri-urban and suburban areas encompassed two clusters which differed in terms of environmental determinants. The highest incidence rates overlapped areas with the highest suitability scores, the strength of association was low though (CSc r = 0.21, P < 0.001 and ESc r = 0.19, P < 0.001). CONCLUSIONS: We present a method to analyze the environmental and socioeconomic suitability for human leptospirosis based on literature and expert knowledge. The methodology can be thought as an evolutive and perfectible scheme as more studies are performed in the area and novel information regarding determinants of the disease become available. Our approach can be a valuable tool for decision-makers since it can serve as a baseline to plan intervention measures.

[Conjunctival changes in a Swiss Braunvieh heifer with malignant lymphoma]. / Veränderungen an den Konjunktiven bei einem Braunviehrind mit malignem Lymphom.

This report describes a 2.8-year-old Swiss Braunvieh heifer with conjunctival changes as the lead clinical signs of malignant lymphoma. The heifer was referred to our clinic because of conjunctivitis that did not respond to treatment with antibiotics. The patient had bilateral lacrimation, severe swelling of the third eyelids and prolapse of the conjunctivae, which were erythematous and covered with haemorrhagic crusts. A clinical examination revealed enlarged prescapular and prefemoral lymph nodes. Based on cytological examination of a fine needle aspirate from a prescapular lymph node, a tentative diagnosis of malignant lymphoma was made. The heifer was euthanased and a postmortem examination carried out. The conjunctival lesions consisted of diffuse multifocal nodules of varying size. There was generalised lymphadenopathy and beige nodules were seen in several internal organs. Histological and immunohistological examinations confirmed the diagnosis of multicentric leukosis characterised by T-cell lymphoblasts, which had also infiltrated the conjunctivae. Examination of a blood sample for enzootic bovine leukosis virus yielded a negative result.

Roles of human disturbance, precipitation, and a pathogen on the survival and reproductive probabilities of deer mice.

Climate change, human disturbance, and disease can have large impacts on the dynamics of a species by affecting the likelihood of survival and reproduction of individuals. We investigated the roles of precipitation, off-road vehicle (ORV) alteration of habitat, and infection with Sin Nombre virus on the survival and reproductive probabilities of deer mice (Peromyscus maniculatus). We used generalized linear mixed models to estimate the effects of these factors and their interactions by fitting capture-recapture data collected seasonally from 2002 to 2007 at 17 sites in the Great Basin Desert of central Utah, USA. During periods with high precipitation, we found no difference in survival and reproductive probabilities between seasons, but during drier periods, we found a reduction of overwinter survival and fall reproductive activity. Precipitation also interacted with disturbance to affect survival probabilities and female reproduction; in periods with low precipitation, deer mice on highly disturbed sites had extremely low survival probabilities and low reproductive probabilities of females compared to those of individuals from low-disturbance sites. However, high precipitation ameliorated the effect of disturbance on both parameters. Deer mice from sites with high impact of ORV disturbance also had low survival over summer. Additionally, male reproductive probabilities were diminished on highly disturbed sites in both seasons; in contrast, they were reduced only in the fall on low-disturbance sites. Density had an overall negative effect on survival and reproductive probabilities of deer mice. For females, the negative effect on reproductive activity was amplified in highly disturbed sites. We found no effect of hantavirus infection on survival probabilities of deer mice. Overall, this study revealed complexity in the determinants of deer mouse survival and reproduction given by the effects of a number of significant interactions among explanatory variables. Thus, factors that may not appear to have a strong effect when investigated alone can still be influential by modulating the effect of a different factor.

Effects of more frequent and prolonged El Niño events on life-history parameters of the degu, a long-lived and slow-reproducing rodent.

Global climate change (GCC) can have profound effects on species whose ecology is governed primarily by climatic factors. The ecology of small mammals inhabiting semiarid Chile is strongly affected by the El Niño Southern Oscillation (ENSO). During La Niña events in this area, dry conditions prevail and species may disappear from the thorn-scrub habitat. Conversely, El Niño events bring high rainfall, and associated pulses of food trigger small-mammal population increases. We used capture-mark-recapture to study responses of the degu (Octodon degus), a dominant small mammal, to variation in rainfall over 18 years. In response to a recent trend toward wetter conditions, degus reached record-high densities and maintained more stable numbers in the area. Underlying mechanisms involved variation in adult survival, juvenile persistence, and fecundity linked to rainfall changes during consecutive years (i.e., rainfall phases). During prolonged droughts, degus had low survival and produced fewer offspring, with low persistence. Following high rainfall, these parameters reversed; consecutive wet years resulted in further increases. Weak declines in fecundity and adult survival and high persistence of juveniles explained delayed responses to deteriorating conditions in initial dry years. If GCC leads to increased frequency of El Niño events, we anticipate greater numerical dominance of degus in semiarid Chile and possible range expansion. Furthermore, degus have strong impacts on other small mammal and some plant species, are important prey species, and are agricultural pests and disease reservoirs. Hence, GCC has the potential to dramatically influence their ecology in northern Chile and to have cascading effects on other components of this system.

Clinical findings and treatment in 63 cows with haemorrhagic bowel syndrome.

The clinical, haematological and biochemical findings, treatment and outcome of 63 cows with haemorrhagic bowel syndrome are described. The general condition and demeanor were moderately to severely abnormal in all the cows. Signs of colic occurred in 27 cows, decreased rectal temperature in 46 and tachycardia in 44. With the exception of one cow, intestinal motility was decreased or absent. Transrectal palpation revealed dilatation of the rumen in 47 cows and dilatation of the small intestine in 18. Faecal output was markedly reduced or absent, and the faeces were dark brown to black and contained blood. Nine cows were euthanized immediately after physical examination. Conservative medical therapy was instituted in two cows; however, both were euthanized a few days later because of deterioration in condition. Exploratory right flank laparotomy was carried out in 52 cows. Of these, 22 were euthanized intraoperatively because of severe lesions. In 27 cows, intestinal massage to reduce the size of blood clots was carried out; 11 were euthanized several days postoperatively because of deterioration in condition. In three other cows, intestinal resection was carried out and all survived. Of the 63 cows, 19 (30.2%) survived and were healthy at the time of discharge from the clinic.

Meta-analysis of risk factors for canine leptospirosis.

Leptospirosis is one of the most widespread zoonotic diseases, with more than one million human cases reported worldwide every year. Dogs could develop infections that range from asymptomatic to severe, and shed leptospires with their urine. Given their close contact with humans, dogs may act both as epidemiological links or as sentinels of pathogenic leptospires in the environment. The aims of our study were to quantitatively summarize the overall prevalence of leptospiral antibodies and to identify factors associated with the probabilities of infection. We searched the electronic databases Scopus, PubMed, PMC and ScienceDirect for observational studies on canine leptospirosis published between 1989 and December 2019 and written in English, Spanish or Portuguese. We fitted a series of multilevel random effects meta-analysis models to estimate the prevalence of antibodies against Leptospira for different types of dogs, health statuses, diagnostic tests, geographic regions and income categories of the countries. We also fitted a number of random effects meta-analysis models to estimate the pooled odds-ratio of factors associated with canine leptospirosis. After removing duplicates and articles not meeting selection criteria, a total of 130 studies in 91 articles were included in this work. We found lower seroprevalence estimates in North America countries (P<0.001) and other high income countries (P<0.001). We also found higher probabilities of leptospiral infection in adult (P=0.017), male dogs with access to the streets (P<0.001). Identifying the profile of dogs that are more exposed to leptospirosis could be useful in the design of public health strategies for the prevention and control of leptospirosis.

Population dynamics of two sympatric rodents in a variable environment: rainfall, resource availability, and predation.

Precipitation plays an important role in the dynamics of species found in arid and semiarid environments. However, population fluctuations generally are driven by a combination of multiple factors whose relative contribution may vary through time and among species. We monitored fluctuations of species in three trophic levels for >17 years at a semiarid community in north-central Chile. The region is strongly affected by the El Niño Southern Oscillation, resulting in high variation in rainfall that triggers dramatic changes in food resource availability, with strong effects on upper trophic levels. We focused our analyses on the role played by endogenous and exogenous (climatic) factors on the dynamics of two important rodent species in the community, Octodon degus and Phyllotis darwini. We documented population fluctuations of several orders of magnitude in response to wet and dry episodes of different strength and duration. P. darwini reached similar maximum densities, regardless of the duration of high-rainfall events, whereas O. degus showed additive effects of multiple wet years. Time series diagnostic tools revealed oscillations with a 5-year periodicity in rainfall, which may be the cause of the same periodicity and a weak second-order signal observed in the rodent dynamics. However, the dynamics of both rodent species were dominated by strong first-order processes, suggesting an important role of direct density dependence. Intraspecific competition, expressed as the ratio of rodent density/rainfall (or food resources) explained more than two-thirds of the variation in the population rate of change, whereas less than one-third was explained by lagged rainfall (or food resources). We detected no significant effects of predation. Our results contribute to a growing number of examples of dynamics governed by the combined effect of density dependence and climatic forcing. They also reveal strong bottom-up regulation that may be common in other arid environments.

Seasonal variation in Sin Nombre virus infections in deer mice: preliminary results.

The proportion of deer mice (Peromyscus maniculatus) with recently acquired Sin Nombre virus (SNV) infections is an indicator of epizootic intensity and may be key in predicting outbreaks of hantavirus cardio-pulmonary syndrome in humans. We investigated whether incidence of recent infections was related to season, sex, reproductive status, or habitat disturbance. In May and September, 2006, we sampled 912 deer mice at six sites in Utah. We determined SNV antibody prevalence and estimated the number of recent infections with an avidity enzyme-linked immunosorbent assay. Antibody prevalence in adults (n = 735) was 22%, and putative maternal antibody prevalence in juveniles (n = 177) was 7%. Sampling period explained a significant amount of the variance in the probability of recent infections, which were two times more common in May versus September. Additionally, prevalence of high-avidity maternal antibodies (i.e., from dams with older infections) in juveniles did not correspond to the antibody avidity patterns in adult females. In May, no juveniles had high-avidity antibodies compared to adult females (49%); in September, avidity could not be measured in juveniles because none were seropositive, despite large sample sizes (n = 84) and an 11% seroprevalence in adult females. Based on the results, coupled with those from the literature, we speculate that the majority of new infections may occur predominantly in the spring and that SNV may impair reproductive output of females.

[Cystoscopy in a heifer with rupture of a patent urachus]. / Zystoskopie bei einem Rind mit Urachus persistens-Ruptur.

This case report describes the clinical, ultrasonographic and cystoscopic findings and treatment in a two-year-old Swiss Braunvieh heifer with rupture of a patent urachus. The lead signs in the seven-month-pregnant heifer were markedly abnormal general condition and demeanour and a pear-shaped abdomen. The heifer had severe azotaemia, and abdominal ultrasonography revealed ascites, which was diagnosed as uroperitoneum based on an elevated creatinine level in the fluid. A patent urachus was identified during cystoscopy; the endoscope could be advanced beyond the apex of the urinary bladder into the urachus. Based on all the findings, a diagnosis of uroperitoneum attributable to rupture of a patent urachus was made. The urachus was ligated twice via a left-flank laparotomy. The general condition normalised within a few days of surgery, and the patient calved normally and was in good health at follow-up evaluation.

An unusual cause of traumatic reticulitis/reticuloperitonitis in a herd of Swiss dairy cows nearby an airport.

This report describes the findings in five cows from one dairy herd, in which all 31 cows were slaughtered or euthanised because of traumatic reticuloperitonitis. All the cows had numerous thin sharp pieces of metal attached to a magnet in the reticulum, giving the magnet a hedgehog-like appearance. Investigation revealed that the cattle had eaten forage harvested from a field immediately adjacent to an airport. The snow was cleared from the airport runways with a machine that had a wire-bristle brush attachment. Mechanical wear resulted in numerous wire bristles breaking and these were blown with the snow onto the field in question. The wire then became accidentally incorporated into the hay and grass silage at harvest the next summer and was ingested by the cattle in the fall and winter. To prevent further cases, approximately 200 tonnes of hay and grass silage contaminated with wire were discarded and 30 hectares of the 50-hectare field were cultivated and re-sown. The wire-bristles of the snow plow were replaced with plastic bristles. The cost of this and the livestock loss was several hundred thousand Swiss Francs.

Sonographic findings in an alpaca with Mycobacterium kansasii infection.

This case report describes the clinical, ultrasonographic and postmortem findings in an alpaca with Mycobacterium kansasii infection. The alpaca was referred because of chronic weight loss and weakness. The results of clinical examination, haematology and serum biochemistry were not diagnostic. Ultrasonography of the liver revealed multiple, hyperechogenic lesions with a diameter of 1 to 3 cm. Histological evaluation of a liver biopsy sample showed acute, multifocal, suppurative, necrotising hepatitis. Despite treatment with antibiotics, the alpaca died. Postmortem examination revealed nodular to coalescing lesions in the liver, lungs, mediastinum, pleura and greater omentum, which could not be differentiated macroscopically or histologically from lesions caused by tuberculosis. Ziehl-Neelsen staining showed massive numbers of rods within epithelioid macrophages, which were identified as Mycobacterium kansasii by polymerase chain reaction analysis.

Orthohantavirus genotype Lechiguanas in Oligoryzomys nigripes (Rodentia: Cricetidae): New evidence of host-switching.

To identify and predict situations of increased risk of orthohantavirus infection in humans, it is necessary to study the relationships between the virus and its rodent hosts. The present study investigated orthohantavirus infection in an assemblage of wild Sigmodontinae rodents of the Paraná Delta, Argentina, and providing new evidence of host-switching events. Rodents belonging to the species Oxymycterus rufus (n = 187), Akodon azarae (n = 82), Oligoryzomys flavescens (n = 80), Oligoryzomys nigripes (n = 47), Scapteromys aquaticus (n = 38), Deltamys kempi (n = 7) and Holochilus brasiliensis (n = 2) were captured at 4 sampling sites during 20 trapping sessions. Blood samples were analyzed by IgG ELISA and livers by a nested reverse transcription PCR for the diagnosis of orthohantavirus infection. The amplified products of the S and M orthohantavirus genomes were sequenced and analyzed to determine similarities with species of the Orthohantavirus genus. The species of the Oligoryzomys positive to the virus were confirmed by amplifying and sequencing the complete cyt b gene. Of the 443 serum samples analyzed by IgG ELISA, A. azarae presented the highest host-specific prevalence value (10/82, 12.2%) followed by Ol. nigripes (4/47, 8.5%) and Ox. rufus (1/187, 0.5%). All the sero-positive Ol. nigripes (n = 4) were positive to the amplification of the S and M segments of the Lechiguanas genotype (98% nucleotide identity for both segments). This is surprising given that Ol. nigripes has been previously associated with Juquitiba genotype, not Lechiguanas. The latter is generally associated with Ol. flavescens, which in our study were all sero-negative. In addition, the association Ox. rufus - Pergamino genotype found here is, to our knowledge, novel and another potential evidence of host-switching considering that Pergamino has been originally associated with A. azarae. These findings contribute to the building evidence that contradicts the one-genotype-one-reservoir species premise in the association between rodent reservoirs and orthohantaviruses, and supports the hypothesis that the community structure of sympatric host species may contribute to orthohantavirus dynamics.

Knowledge, attitudes and practices (KAP) regarding leptospirosis among residents of riverside settlements of Santa Fe, Argentina.

BACKGROUND: Leptospirosis is a global and re-emerging zoonotic disease caused by Leptospira spirochetes that are shed into the environment by infected animals. Humans can get infected via contact with animal hosts or contaminated environment. In Argentina, the highest annual incidences were reported in the province of Santa Fe, where epidemic outbreaks occurred during flooding events. This study examined the knowledge, attitudes and practices (KAP) regarding leptospirosis among residents of riverside slum settlements from Santa Fe after a major flood. METHODS AND FINDINGS: A cross-sectional questionnaire was administered to 113 residents of 3 riverside settlements from Santa Fe. The influence of knowledge and attitudes regarding leptospirosis on the likelihood that an individual will use preventive practices were evaluated using linear mixed-effects models. The majority of respondents (83.2%) had previously heard about leptospirosis; however specific knowledge about leptospirosis was limited. The results of the modeling efforts, show that the likelihood of using preventive practices was associated with having greater knowledge score, but not with more positive attitudes. We also found that females were more likely to use safer practices than males. CONCLUSIONS: Even though the majority of respondents had heard about leptospirosis, a high percentage of them had limited knowledge regarding the severity of the disease and its prevalence in the region. Our results suggest that public health interventions in these riverside communities should focus on educating the public on the multiple dimensions of leptospirosis in order to attain greater adherence to preventive practices instead of intending to change the perceptions or attitudes towards the disease, which did not have a significant influence. The key challenge lies in identifying effective strategies to reach the high risk group for leptospirosis here that is male fishermen, who spend most of the time in precarious campsites on the river islands.

Echocardiographic evaluation of left ventricular diastolic function: correlation between echocardiographic and hemodynamic parameters.

AIM: The aim of this study was to assess the correlation between non invasive echo-Doppler parameters of diastolic function and invasively measured end-diastolic left ventricular (LV) filling pressures in patients with normal or depressed LV function. METHODS: The patient population was composed of 44 subjects, (34 men and 10 women) 52% with normal ventricular function, who underwent echo-Doppler and hemodynamic evaluation within 24 hours between the two exams. RESULTS: LV end-diastolic pressure was statistically different (P=0.022) in the 4 subgroups divided on the basis of the mitral flow pattern in the overall population and in the patients with depressed LV function, but not in those with normal LV function. In the overall population LV end-diastolic pressure was significantly correlated with: 1) E/A ratio of mitral flow (r=0.45, P=0.002); 2) mitral E wave peak velocity (r=0.39, P=0.017); 3) isovolumic relaxation time (r=-0.34, P=0.01); 4) left atrial diameter (r=0.33, P=0.037); 5) duration of retrograde A wave of pulmonary venous flow (r=0.33, P=0.03); 6) Pulmonary vein D wave peak velocity (r=0.29, P=0,05). Multivariate analysis showed that the correlation between the echo-Doppler variables and LV end-diastolic pressure was statistically significant only in patients with depressed LV function, but not in those with normal function. CONCLUSION: Among the echo-Doppler variables examined, those derived from transmitral flow and pulmonary vein flow show the best correlation with left ventricular end-diastolic pressure; however, the correlation is statistically significant only in patients with depressed LV function. Thus, the echo-Doppler evaluation of LV diastolic function should take into account this limitation and should be based on a multiparametric approach.