Serovar Pomona Research Articles

Serological patterns, antibody half-life and shedding in urine of Leptospira spp. in naturally exposed sheep

AIMS: To determine within-farm prevalence, longitudinal pattern of exposure measured by serology, antibody titre longevity and point prevalence of shedding in urine of Leptospira borgpetersenii serovar Hardjo and L. interrogans serovar Pomona in naturally infected sheep on a sample of commercial farms in New Zealand.METHODS: On eight commercial sheep farms, between September 2011 and January 2014, blood samples were collected from 115–217 ewe lambs on each farm, at intervals of 2–11 months. They were analysed by microscopic agglutination test (MAT) for antibodies to L. borgpetersenii serovar Hardjo and L. interrogans serovar Pomona, using a titre cut-point of 48. Urine from 98 animals was tested by quantitative PCR (qPCR). The half-life of antibodies was estimated in 185 sheep for serovar Hardjo and 21 for Pomona, and the seroprevalence and mean titre of animals lost to follow-up was compared with those remaining in the study.RESULTS: Within-flock seroprevalence for serovar Hardjo reached a maximum at 17–22 months of age, ranging from 79 to 100%. Seroprevalence for serovar Pomona rose above 10% on three farms and increased to 21–54% by 4–14 months. Seroconversions occurred mainly from late autumn to early summer at 7–15 months of age. Seroprevalences ranging from 3 to 76% for serovar Hardjo and 0.5 to 15% for serovar Pomona were observed up to 3 months of age, likely due to maternally derived immunity. The half-life of antibody in response to infection was estimated to be 6.7 (95% CI=5.8–7.9) months for serovar Hardjo and 6.3 (95% CI=4.8–9.0) months for Pomona. The prevalence of sheep with urine positive for leptospires on qPCR on each farm ranged from 11 to 88%. All but one of the qPCR-positive animals were seropositive for serovar Hardjo. On two farms where Pomona exposure was observed, animals that were lost to follow-up had a higher geometric mean titre for serovar Pomona than those remaining in the study.CONCLUSIONS: This study demonstrated seasonal exposure from autumn to early summer in young sheep, a wide range of within-flock serological and shedding prevalence, and gives an estimation of the half-life of MAT titres in sheep. More extensive data are needed to fully understand the epidemiology of leptospirosis in sheep flocks across New Zealand and, along with economic analysis, to justify and design cost-effective and efficient control measures to protect human and animal health.

Factors associated with fetal losses in ewe lambs on a New Zealand sheep farm

CASE HISTORY: As part of a production study of ewe lambs on a large farm in the Waikato region of New Zealand in 2011, pregnancy diagnosis was undertaken twice by trans-abdominal ultrasonography at 68–103 and 97–132 days of gestation. At the second pregnancy diagnosis 257/3,790 (6.8%) ewe lambs had evidence of non-viable fetuses or absence of a pregnancy that was present at the previous pregnancy diagnosis (fetal loss).LABORATORY FINDINGS: Serum antibody titres for Leptospira interrogans serovar Pomona appeared generally higher in 10 ewe lambs with fetal loss compared with 10 that were still pregnant. Histopathological investigation was not able to confirm that fetal loss was associated with leptospial infection.EPIDEMIOLOGICAL INVESTIGATION: In the 2012-born cohort of ewe lambs 443 were vaccinated with a bivalent leptospirosis vaccine and 882 unvaccinated. Serum was collected from 124 non-vaccinated ewe lambs between January and December 2013 for measurement of antibodies to Leptospira serovar Pomona and L. borgpetersenii serovar Hardjo-bovis using a microscopic agglutination test (MAT). Less than 5% of these ewe lambs were seropositive until May, but by August 85% and 48% of animals were seropositive to Leptospira serovars Hardjo-bovis and Pomona, respectively.Fetal loss in non-vaccinated ewe lambs was 78/882 (9%) compared with 23/443 (5%) in vaccinated ewe lambs. Combined data from the 2011- and 2012-born ewe lambs (n=5,115) were analysed using a logistic regression model and fetal loss as the dependent variable. In the final model fetal loss was associated with pre-mating bodyweight (p=0.003), weight change from pre-mating to initial pregnancy diagnosis (p<0.001), year born and leptospirosis vaccination status (p=0.013). Amongst the serologically monitored ewe lambs, there were associations between fetal loss and being seropositive to Leptospira serovar Pomona using titre cut-points of 1:48 and 1:768 (p<0.001).CLINICAL RELEVANCE: Low pre-mating weight and/or low weight gain from mating to pregnancy diagnosis was associated with increased fetal loss, emphasising the importance of ewe lambs achieving target pre-mating weights and liveweight gains during pregnancy. Infection with Leptospira serovar Pomona was associated with fetal loss in the 2012-born cohort and the possibility of infection with this serovar should be considered when investigating cases of fetal loss.

Safety and efficacy of a new octavalent combined Erysipelas, Parvo and Leptospira vaccine in gilts against Leptospira interrogans serovar Pomona associated disease and foetal death

The safety and protective efficacy of a new octavalent combination vaccine containing inactivated Erysipelothrix rhusiopathiae, Parvovirus, and Leptospira interrogans (sensu lato) serogroups Canicola, Icterohaemorrhagiae, Australis (Bratislava), Grippotyphosa, Pomona and Tarassovi – Porcilis® Ery+Parvo+Lepto – was evaluated in laboratory studies and under field conditions.The safety (2× overdose and repeated dose) was tested in 26 gilts. In this study, neither vaccine related temperature increase nor other systemic reactions were observed after intramuscular vaccination. No local reactions were observed except for one animal that had a small local reaction (2cm diameter) that lasted for 5 days after the third vaccination.Efficacy was tested in 40 gilts. A group of 20 gilts was vaccinated at 20 and 24 weeks of age with Porcilis® Ery+Parvo+Lepto and a group of 20 age- and source-matched animals served as the control group. The gilts were inseminated at 41 weeks or 66 weeks of age and were challenged with serovar Pomona 10 weeks after insemination, corresponding to 6 months (n=2×10) and 12 months (n=2×10) after the last vaccination. After both the 6- and 12-month challenges the control animals developed clinical signs (fever, lethargy and anorexia) and leptospiraemia as determined by positive blood culture. In addition, both the 6- and 12-month challenges resulted in death of 21% and 27% of the total number of foetuses in the control groups, respectively. Clinical signs and leptospiraemia were statistically significantly lower in vaccinated gilts after both the 6- and 12-month challenges. In addition, foetal death was statistically significantly lower (3% and 2%, respectively) in vaccinated gilts after both the 6- and 12 month challenges.The vaccine was tested further under field conditions on a Portuguese farm with a history of an increasing abortion rate associated with a Leptospira serovar Pomona infection (confirmed by PCR and serology). This study was designed as an observational-longitudinal field study. At the start of the study, all breeding sows and replacement gilts on the farm were vaccinated twice with Porcilis® Ery+Parvo+Lepto at an interval of 4 weeks. Starting six months after the primary vaccination schedule, the animals were re-vaccinated during the second week of every subsequent lactation. New replacement gilts were vaccinated using the same schedule. After vaccination, the abortion rate reduced rapidly from 12.6% in winter months of 2012 (December 2011 to March 2012) to 0.5% in winter months of 2013, a statistical significant decrease of 96%. The total number of abortions on the farm decreased from 55 in 2012 to 6 in 2013. Thereafter, the abortion rate remained stable and in the period December 2013 to April 2014 was still low (0.6%).In conclusion, the present studies demonstrate that the octavalent Porcilis® Ery+Parvo+Lepto vaccine can be safely used in gilts and sows and induces significant protection, for the duration of at least one year, against serovar Pomona induced clinical signs, leptospiraemia and foetal death. Protection against Pomona associated reproductive failure was confirmed under field conditions where a significant reduction in abortion rate was observed.

Leptospirosis in animals and human contacts in Egypt: broad range surveillance.

Leptospirosis is a re-emerging zoonotic disease of humans and animals worldwide. The disease is caused by pathogenic species of the genus Leptospira. These organisms are maintained in nature via chronic renal infection of carrier animals, which excrete the organisms in their urine. Humans become infected through direct or indirect exposure to infected animals and their urine or through contact with contaminated water and soil. This study was conducted to investigate Leptospira infections as a re-emerging zoonosis that has been neglected in Egypt. Samples from 1,250 animals (270 rats, 168 dogs, 625 cows, 26 buffaloes, 99 sheep, 14 horses, 26 donkeys and 22 camels), 175 human contacts and 45 water sources were collected from different governorates in Egypt. The samples were collected from different body sites and prepared for culture, PCR and the microscopic agglutination test (MAT). The isolation rates of Leptospira serovars were 6.9%, 11.3% and 1.1% for rats, dogs and cows, respectively, whereas the PCR results revealed respective detection rates of 24%, 11.3% and 1.1% for rats, dogs and cows. Neither the other examined animal species nor humans yielded positive results via these two techniques. Only six Leptospira serovars (Icterohaemorrhagiae, Pomona, Canicola, Grippotyphosa, Celledoni and Pyrogenes) could be isolated from rats, dogs and cows. Moreover, the seroprevalence of leptospiral antibodies among the examined humans determined using MAT was 49.7%. The obtained results revealed that rats, dogs and cows were the most important animal reservoirs for leptospirosis in Egypt, and the high seroprevalence among human contacts highlights the public health implications of this neglected zoonosis.

Seroprevalence of Leptospirosis in Clinically Ailing Bovine

The purpose of this study was to carried out seroepidemiological study of leptospirosis in clinically ailing cattle and buffaloes of South Gujarat where cases of leptospirosis in human is increase every monsoon since last decade. To determine clinical pattern of bovine Leptospirosis in this area a total of 130 serum samples of cattle and buffaloes were collected randomly from different age groups of cattle and buffaloes of either sex reared in this area and tested by microscopic agglutination test (MAT) using different serovars of Leptospira spp. The prevalence of leptospiral antibodies was detected in 15.84 and 17.24% in clinically ailing cattle and buffaloes, respectively. In clinically ailing seropositive cattle history of mastitis/agalactia/oligolactia was recorded in maximum number of cases (24.00%) followed by abortion (20.00%), fever (14.81%), repeat breeding (11.76%) and anorexia (5.88%) in different combinations. In seropositive clinically ailing buffaloes the clinical signs included mastitis (30.00%), fever (16.66%) and abortion (14.28%). In clinically ailing cattle highest prevalence was noted in animals above 4 years of age (20.00%) followed by 1–4 years of age (4.76%) whereas in clinically ailing buffalo seropositivity was recorded only in above 4 years of age (20.00%). The most prevalent serovar pomona has been reported from different clinical conditions in both cattle and buffaloes. Based on present and few past investigation reports the sero-epidemiological condition of bovine leptospirosis that need due attention as South Gujarat region is endemic zone for leptospirosis.

Recombinant antigens rLipL21, rLoa22, rLipL32 and rLigACon4-8 for serological diagnosis of leptospirosis by enzyme-linked immunosorbent assays in dogs.

Animal leptospirosis is one of the most common zoonotic diseases in the United States and around the world. In a previous study, we applied four recombinant antigens, rLipL21, rLoa22, rLipL32 and rLigACon4-8 of Leptospira interrogans (L. interrogans) for the serological diagnosis of equine leptospirosis (Ye et al, Serodiagnosis of equine leptospirosis by ELISA using four recombinant protein markers, Clin. Vaccine. Immunol. 21:478–483). In this study, the same four recombinant antigens were evaluated for their potential to diagnose canine leptospirosis by ELISA. A total of 305 canine sera that were Leptospira microscopic agglutination test (MAT)-negative (n = 102) and MAT-positive (n = 203) to 5 serovars (Pomona, Grippotyphosa, Icterohaemorrhagiae, Canicola and Hardjo) were tested. When individual recombinant antigens were used, the sensitivity and specificity of ELISA were 97.5% and 84.3% for rLigACon4-8; 89.7% and 81.4% for rLoa22; 92.6% and 84.3% for rLipL32 and 99.5% and 84.3% for rLipL21, respectively compared to the MAT. The sensitivity and specificity of ELISA were, 92.6% and 91.2% for rLigACon4-8 and rLipL32, 97.5% and 84.3% for rLigACon4-8 and rLipL21, 89.7% and 87.3% for rLigACon4-8 and rLoa22, 89.7% and 87.3% to rLipL21 and rLoa22, 92.6% and 91.2% for rLipL21 and rLipL32 and 89.2% and 94.1% for rLoa22 and rLipL32 when one of the two antigens was test positive. The use of all four antigens in the ELISA assay was found to be sensitive and specific, easy to perform, and agreed with the results of the standard Leptospira Microscopic Agglutination test (MAT) for the diagnosis of canine leptospirosis.

Seroepidemiological pattern of leptospirosis in bovine of South Gujarat, India

Aim: Seroepidemiological study of leptospirosis in cattle of various South Gujarat district (Navsari, Tapi, Surat, Valsad). Materials and Methods: Whole blood samples were collected randomly from different age groups, and breeds of cattle of either sex reared in different districts (Navsari, Surat, Tapi, Valsad) of South Gujarat. To obtain serum, whole blood was kept in slanting position in 9.0 ml plain vacutainers until serum extracted out of the whole blood. Then these 9.0 ml plain vacutainers were centrifuged at 7000 rpm for 10 min. The straw colored serum was then collected in 1.5 ml sterile cryo vials and aliquoted and stored at −20°C for microscopic agglutination test. Results: In the present study, overall 12.81% (51/398) seroprevalence were recorded with highest seroprevalence (47.06%, 24/51) from Valsad followed by Navsari (9.14%, 18/197), Surat (6.90%, 2/29) and Tapi (5.79%, 7/121) among cattle. The seroprevalence rate of breed and sex wise did not differ significantly (p≤0.05). Maximum incidence of seropositivity was found above 4 years (16.32%, 39/239) of age group followed by animals between 1 and 4 years (9.68%, 12/124). Thus, the age was significantly influencing the seropositivity (p≤0.05). In cattle out of 398 sera screened, 51 were positive with one or more serovars. The highest seropositivity was recorded against serovar Pomona (28.89%). Conclusions: Overall 12.81% seroprevalence of leptospirosis in apparently healthy and clinically ailing bovine of South Gujarat indicating potential zoonotic risk to farmers, labor, and animal owners.

Risk factors associated with leptospirosis in dogs from Northern California: 2001-2010.

The present study was performed to identify risk factors for canine leptospirosis at a tertiary referral institution in northern California from 2001 through 2010 and to describe case characteristics. In this retrospective case-control study, 67 dogs with leptospirosis and 271 controls were evaluated at the William R. Pritchard Veterinary Medical Teaching Hospital (Davis, CA) from March, 2001 , through November, 2010. Medical records of cases and controls were analyzed to identify signalment, exposure history, and clinical signs that increased the risk for a diagnosis of leptospirosis. Among cases, most were vomiting and lethargic and had leukocytosis and azotemia. Total white cell count, neutrophil count, and monocyte count were higher in dogs with leptospirosis, whereas the platelet count was lower. Serum concentrations of urea nitrogen, creatinine, and bilirubin were elevated in dogs with leptospirosis as well. On average, case dogs were hospitalized for 11 days and had hospital bills exceeding $5000. Mortality was 13% of case dogs, with the predominant serovar being Pomona. Dogs with leptospirosis were more likely to reside in the central or south coast (odds ratio [OR]=7.33), Sierra Nevada foothills (OR=4.50), San Francisco Bay area (OR=4.2), and north coast (OR=2.85) of California when compared with controls. Dogs 5-10 years old (OR=3.22) or over 10 years old (OR=2.76) and herding (OR=3.1) or hound breed (OR=4.6) dogs were more likely to have leptospirosis than the control group. Leptospirosis was associated with acute renal failure in older, undervaccinated dogs. The regional distribution, large breed predisposition, and finding of predominantly Pomona serovar suggest wildlife or other contacts as an important route of exposure. Knowledge of risk factors, vaccination history, and clinical signs can increase an index of suspicion for leptospirosis and contribute to improved strategies for prevention of leptospirosis in dogs, understanding of the ecology of the disease for all species, and protection of human health.

Cross-protection between experimental anti-leptospirosis bacterins.

We investigated the existence of cross-protection between two anti-leptospirosis monovalent experimental bacterins produced with two strains of Leptospira serogroup Pomona: Fromm strain of serovar Kennewicky, isolated from pigs in the United States, and strain GR6 of serovar Pomona isolated from pigs in Brazil. Both were added of aluminum hydroxide as an adjuvant. Experimental bacterins were tested with the hamster potency test in order to assess protection provided against the disease and against the establishment of kidney infection. Controls were polyvalent commercial vaccine produced with Leptospira strains isolated outside Brazil, which included a representative of Pomona serovar, or Sorensen solution added of aluminum hydroxide adjuvant. The challenge was performed with cross-strains of serogroup Pomona tested in accordance with international standards established for the potency test. After 21 days of the challenge, survivors were killed to evaluate the condition of Leptospira renal carrier. Experimental bacterins protected hamsters against homologous and heterologous strains, demonstrating the existence of cross-protection. The commercial vaccine protected the hamsters challenged with both strains, but there was a high proportion of animals diagnosed as renal carriers when the challenge was performed with strain GR6, isolated from pigs in Brazil.

Enfermedad de Carrión grave complicada con leptospirosis aguda: reporte de un caso

The case of an adult, 56 year old male is reported, from Sihuas (Ancash) who presented at Hospital Nacional Dos de Mayo with fever, jaundice and anemia. In three days of hospitalization, he developed severe anemia (Hb: 11.8 to 6.7 g / dL) and generalized myalgias associated with a sudden worsening jaundice correlated with elevated bilirubin (TB 3.2 to 19.6 mg / dL direct dominance) and general deterioration. Microbiological smear and culture were positive for Bartonella bacilliformis. Subsequent serology (microagglutination) was positive for Lesptospira serovar Pomona. The patient was given specific antibiotic therapy (ceftriaxone and ciprofloxacin), transfused two units of packed red blood cells, improved clinically and was discharged.

Genotypes of Leptospira spp. strains isolated from dogs in Buenos Aires, Argentina

Leptospirosis is an infectious disease of wide global distribution, which is endemic in Argentina. The objective of this study was to obtain the genetic profiles of Leptospira spp. strains isolated from clinical cases of dogs in the province of Buenos Aires by the multiple-locus variable-number tandem repeat analysis (MLVA). Eight isolated canine strains were genotyped by MLVA, obtaining the identical profile of Leptospira interrogans serovar Canicola Hond Utrecht IV in the strains named Dogy and Mayo. The strains named Bel, Sarmiento, La Plata 4581 and La Plata 5478 were identical to the profile of the genotype of L. interrogans serovar Portlandvere MY 1039.The strain named Avellaneda was identical to the genotype profile of L. interrogans serovar Icterohaemorrhagiae RGA and the strain named SB had the same profile as the L. interrogans serovar Pomona Baires genotype and was similar to the profile of serovar Pomona Pomona genotype. It would be useful to include a larger number of isolates from different dog populations in various provinces of Argentina and to characterize the genetic profiles of the strains circulating in the country. The information obtained will be useful for the control of leptospirosis in the dog population.

Involvement of Leptospira serovars with Different Clinical Conditions of Leptospirosis in Cattle

Leptospirosis is a worldwide zoonosis affecting domestic animals, pet animals, wild animals and human beings. It causes abortion, repeat breeding, jaundice and haemorrhagic mastitis in bovines. The present study was undertaken to understand the involvement of different leptospiral serovars with different clinical conditions of leptospirosis among bovines. A total of 1122 serum samples collected from cattle with different clinical conditions which included abortion (247), repeat breeding (429), jaundice (215), haemorrhagic mastitis (231) were subjected to Microscopic agglutination test. The study revealed the association of hardjo with abortion (21.98 per cent), repeat breeding (47.25 per cent), jaundice (15.38 per cent) and haemorrhagic mastitis (15.38 per cent). The serovar pomona was associated with abortion (19.67 per cent), repeat breeding (39.34 per cent), jaundice (21.31 per cent) and haemorrhagic mastitis (19.67 per cent). Serovar hebdomadis was associated with abortion (29.48 per cent), repeat breeding (37.17 per cent), jaundice (16.67 per cent) and haemorrhagic mastitis (16.67 per cent). Serovar ballum was found to associate with abortion (18.75 per cent), repeat breeding (46.87 per cent), jaundice (15.62 per cent) and haemorrhagic mastitis (18.75 per cent). In addition, the serovar australis was found to associate with abortion (19.29 per cent), repeat breeding (42.10 per cent), jaundice (19.29 per cent) and haemorrhagic mastitis (19.29 per cent). However from this study, serovar specificity with regard to clinical conditions in cattle could not be established as all the five serovars were involved with different clinical conditions.

Isolation of Leptospira from a phocid: acute renal failure and mortality from Leptospirosis in rehabilitated northern elephant seals (Mirounga angustirostris), California, USA.

During rehabilitation, acute renal failure due to leptospirosis occurred in eight male northern elephant seals (Mirounga angustirostris) that stranded along the central California coast in 2011. Characteristic histologic lesions including renal tubular degeneration, necrosis, and mineralization, and mild lymphoplasmacytic interstitial nephritis were noted in the six animals examined. Immunohistochemistry, bacterial culture, and PCR were positive in 2/3, 2/3, and 3/4 seals, respectively, and 6/8 had high serum antibody titers to Leptospira interrogans serovar pomona. Pulsed-field gel electrophoresis confirmed one isolate as serovar pomona. Variable number tandem repeat (VNTR) analysis showed both elephant seal isolates were identical to each other but distinct from those isolated from California sea lions (Zalophus californianus). The time from stranding to onset of azotemia was 1 to 38 (median=24) days, suggesting some seals were infected at the rehabilitation facility. Based on temporal and spatial incidence of infection, transmission among elephant seals likely occurred during rehabilitation. Molecular (VNTR) analysis of the two isolates indicates there is a unique L. interrogans serovar pomona genotype in elephant seals, and sea lions were not the source of infection prior to or during rehabilitation. This study confirms the susceptibility of northern elephant seals to leptospirosis, indicates intraspecies transmission during rehabilitation, and reports the first isolation and preliminary characterization of leptospires from elephant seals.

Seroprevalence of Leptospira infection in bats roosting in human settlements in Morogoro municipality in Tanzania.

Leptospirosis is a neglected emerging infectious disease with high burden in Africa. Major reservoirs of leptospirosis are rodents and other small mammals. Studies of leptospirosis in bats and the extent to which they contribute to its transmission to humans and domestic animals in Tanzania are lacking. The objective of this study was to determine the prevalence of leptospirosis and local Leptospira serovars in bat colonies found around human settlements in Morogoro, Tanzania. In this study, mist nets were used to capture bats at Sokoine University of Agriculture main campus, whereas bats roosting on trees at Nunge A, Nunge B and M were primary school were captured manually. Leptospirosis was determined using the gold standard microscopic agglutination test for determination of Leptospira antibodies. Six live Leptospira serovars including local Leptospira serovar Sokoine, Kenya and Lora reported in rodents and domestic animals in Tanzania, and reference serovars Hebdomadis, Canicola and Pomona were used in the study. Leptospirosis prevalence was high in bats (19.4%) and higher within colonies (27.3%). Leptospira serovar Sokoine was more prevalent (19.4%) compared to serovars Kenya (2.8%) and Lora (2.8%). Serovars Pomona, Canicola and Hebdomadis were not detected in bats. In conclusion, bats are potential reservoir and transmitter of Leptospira serovar Sokoine, hence should be prevented to access houses and roosting in human settlements to avoid public health risks. Routine diagnosis of human leptospirosis is needed in Tanzania as evidence show a high prevalence of Leptospira in reservoir hosts interacting with humans.

Seroepidemiología de la leptospirosis en bovinos con trastornos reproductivos en el municipio de Montería, Colombia

Se realizó un estudio descriptivo para determinar la prevalencia de leptospirosis en bovinos con trastornos reproductivos de zonas rurales de Montería, Colombia. Se colectaron muestras de suero de 26 toros y 137 vacas procedentes de 28 fincas con antecedentes de problemas reproductivos, los cuales fueron analizados mediante técnica de microaglutinación (MAT) para detección de anticuerpos contra Leptospira. Se utilizaron antígenos de los serovares pomona, hardjo, canicola, grippotyphosa e icterohaemorrhagiae. El 41 % de los sueros fue positivo a Leptospira a punto de corte 1:20. Los serovares prevalentes fueron grippotyphosa (29,85 %) hardjo e icterohaemorrhagiae (20,8 y 16,41 %). Se realizó una prueba de chi cuadrado (χ2) para establecer relación entre la seropositividad a Leptospira y las variables de sexo, edad, antecedentes de abortos y repetición de servicios de cada animal, así como zona de muestreo y sistema de producción de las fincas. La seropositividad a Leptospira fue de 26,86 % y 29,85 % en los grupos de edad de 3-4 años y de 5-6 años, y del 43,2 % en bovinos ≥ 7 años. La seroprevalencia en vacas abortadas y no abortadas fue similar (35 y 34 %); asimismo, la seropositividad en vacas con y sin repeticiones de servicio fue de 34 y 35 %, respectivamente. El 41,7 % de las fincas con sistema de producción de carne y el 58,2 % con doble propósito fueron positivas a diferentes serovares. Sin embargo, no se encontró dependencia entre la seropositividad a Leptospira y las variables mencionadas (p &gt; 0,05). Los resultados indican una alta seroprevalencia de leptospirosis en bovinos con trastornos reproductivos del municipio de Montería.

The serological response of working farm dogs to a vaccine containing Leptospira interrogans serovars Copenhageni and Pomona, and L. borgpetersenii serovar Hardjo

AIMS: To evaluate the serological response in dogs to a commercial vaccine for use in cattle containing cultured strains of Leptospira interrogans serovars Copenhageni and Pomona, and L. borgpetersenii serovar Hardjo.METHODS: Blood samples were obtained from 67 working farm dogs on 12 farms, and the microscopic agglutination test (MAT) was used to measure titres to the Leptospira spp. serovars Pomona, Hardjo, and Copenhageni. Samples with a titre of <1:25 were defined as seronegative. Dogs that were seronegative to both Pomona and Hardjo (n=33) were randomised to either the vaccination (n=20) or control (n=13) groups. Seven of these dogs were seropositive to Copenhageni. Vaccinated dogs were given the three-component vaccine subcutaneously on two occasions, 4 weeks apart. MAT titres were measured again in both groups 2 weeks after the second vaccination.RESULTS: Of the vaccinated dogs, 20/20 (100%) developed titres to serovar Pomona, and 16/20 (80%) had titres >100; for serovar Hardjo, 19/20 (95%) dogs had titres, with 18/20 (90%) being >100; and for serovar Copenhageni, 15/17 (88%) dogs that were initially seronegative had titres, with 6/17 (35%) being >100. The median titres for Pomona and Hardjo (200 (95% CI=179–359) and 200 (95% CI=176–379), respectively) were lower than for Copenhageni (50 (95% CI=26–124)) in dogs originally seronegative (p<0.001). There was no association between titres to the different serovars. Of the 13 unvaccinated dogs, two developed titres to serovar Pomona, and three to Hardjo. All titres were <100.CONCLUSIONS: The tested vaccine was effective in raising antibodies to the three serovars, although the titres do not guarantee protection.CLINICAL RELEVANCE: There has been a recent increase in cases of leptospirosis attributed to the serovar Pomona in dogs in New Zealand, but the vaccines licensed for use in dogs in New Zealand for the prevention of leptospirosis only protect against Copenhageni/Icterohaemorrhagiae. The vaccine tested in this study produced titres to Pomona and Hardjo that suggest the vaccine could be useful for reducing disease caused by these serovars in working dogs in New Zealand.

Two cases of equine pregnancy loss associated with Leptospira infection in England

INFECTION with Leptospira can cause abortions and stillbirths in domestic cattle, sheep and pigs, as well as in wild animals. It has also been well documented as a cause of...

SEROPREVALENCIA DE ANTICUERPOS CONTRA SEROVARES DE Leptospira spp EN YEGUAS DE UN HARAS DE LA CIUDAD DE LIMA.

The seroprevalence of Leptospira spp in mares with abortion problems in a stud in Lima was determined. Two blood samples were collected from each mare within a 2-month period for the detection of antibodies against 12 Leptospira serovars using the microaglutination test. The serovars included in the study were icterohaemorraghiae, canicola, pomona, bratislava, georgia, tarassovi, autumnalis, pyrogenes, hardjo, ballum, australis and gryppotyphosa. Total prevalence of Leptospira spp was 96 and 100% in the first and second sampling respectively. Antibodies against serovars canicola, icterohaemorraghiae, pomona and georgia were more frequently detected during both period of sampling. No antibodies were found against serovars bratislava, tarassovi, autumnalis, hardjo, australis or gryppotyphosa. Sixty five percent of the animals were positive for three serovars simultaneously. The most frequent serovar was georgia (100%), which has not been reported as a pathogen for horses. The study showed the wide distribution of various Leptospira serovars in horses.

COMPARATIVE SEROPREVALENCE OFLEPTOSPIRA INTERROGANSIN COLOMBIAN MAMMALS ALONG A CLIMATIC GRADIENT

Leptospirosis is a widespread zoonotic disease with well-established impacts on human health in tropical and subtropical regions. Although Leptospira spp. are known to readily infect many wildlife species, the understanding of interspecies and climatic variability in patterns of infection in Neotropical mammals is limited. To improve the understanding of this interplay, 85 mammals representing 17 species were sampled from four Colombian zoos along a climatic gradient. Prevalence of the 21 primary serovars against Leptospira interrogans was determined using the microagglutination test. Individuals were considered positive for a given serovar if antibodies were observable at a 1:100 dilution or greater. Overall prevalence was 9.52%, with positive titers to serovar hurstbridge in Carnivora (Canidae); serovar sarmin in Primata (Atelidae); and serovars australis, mini, autumnalis, pomona, icterohaemorrhagiae, and seramanga in Primata (Cebidae). Prevalence was positively correlated with humidity and temperature, with significantly higher prevalence at the site characterized by high humidity, severe flooding because of rainfall, and warm weather throughout the year. All positive animals were classified as clinically asymptomatic, meaning that antibodies from a current or past infection were detected but no overt symptoms were apparent. The diversity of serovars observed and the taxon-specific nature of these associations suggest that the epidemiology of Leptospira transmission is likely to be complex and multidimensional. The strong association observed between prevalence and climate suggests that the important role of climate as an indicator of Leptospira infection risk in humans may also be applicable to wildlife. Future studies in both wild and captive populations of Neotropical wildlife will further elucidate this disease interplay.

SEROPREVALENCIA A SEROVARES DE LEPTOSPIRAS PATÓGENAS EN ALPACAS Y VICUÑAS DE LOS DEPARTAMENTOS DE HUANCAVELICA Y AYACUCHO, PERÚ.

A serologic study was conducted on 793 alpaca and 195 vicuna sera samples collected in Huancavelica and Ayacucho departments in Peru to detect specific antibodies against five pathogenic leptospira serovars (L. icterohaemorrhagiae, L. pomona, L. canicola, L. wolfii and L. ballum) by the microaglutination test. The survey revealed that 89.6% of the alpacas and 77.4% of vicunas were positive to one or more serovars. In alpacas, the titers varied from 1:100 to 1:1600 reacting mainly to L. icterohaemorrhagiae (43.4%) and L. pomona (37.8%), whereas titers among vicunas varied from 1:100 to 1:400 reacting similarly to L. icterohaemorrhagiae (69.2%) and L. pomona (8.2%) serovars. The alpacas also had antibodies to L. canicola (7.8 %) and L. wolfii (0.6%) serovars. These results show that the animals had previous exposure to at least 4 of the 5 serovars tested and the elevated titers to L. icterohaemorrhagiae and L. pomona serovars in alpacas suggest a recent infection event.