The Presence of a Virulent Clone of Leptospira interrogans Serovar Canicola in Confirmed Cases of Asymptomatic Dog Carriers in Mexico.

Leptospirosis is a neglected zoonotic disease that commonly affects cattle, pigs, horses, and dogs in many countries. Infection in dogs is usually subclinical, but acute cases of leptospirosis may occur along with systemic failure, which may become fatal. After recovery from an acute infection, dogs may become asymptomatic carriers and shed pathogenic leptospires through urine for long periods of time. Here, a study of ten different cases of leptospirosis is presented, showing the relevance of dogs as asymptomatic carriers of pathogenic Leptospira. The diagnosis was confirmed via isolation and further serological and genetic identification. Four Leptospira isolates (LOCaS28, 31, 34, and 46) were obtained from the kidneys and urine samples of 58 dogs destined for destruction (6.89%) at a Canine Control Center in Mexico City. No spirochetes were observed in the urine samples of those Leptospira-positive dogs examined under dark-field microscopy, and no clinical signs of disease were observed either. Six additional isolates were obtained: two came from asymptomatic carrier dogs (CEL60 and UADY22); another isolate came from an asymptomatic dog that was a pack companion of a clinically ill dog with fatal leptospirosis (AGFA24); and finally, three isolates were taken from dogs that died of leptospirosis (LOCaS59, Citlalli, and Nayar1). Nine out of the ten isolates were identified as being from the serogroup Canicola via cross-absorption MAT using reference strains and specific antisera, and their identity was genetically confirmed as Canicola ST34 via multi-locus sequencing typing (MLST). In contrast, the isolate Nayar1 was identified as serovar Copenhageni ST2. Interestingly, the asymptomatic dogs from which Leptospira isolates were recovered consistently showed high antibody titers in the microscopic agglutination test (MAT), revealing values of at least 1:3200 against serogroup Canicola and lower titer values against other serogroups. Isolates showed different virulence levels in the hamster model. Taken as a whole, all these findings confirmed that dogs may act as asymptomatic carriers of pathogenic leptospires and possibly spread them out to the environment, thus representing an active public health risk. The results also showed that the Canicola ST34 clone is the most prevalent Leptospira serovar in dogs in Mexico, and finally that the old-fashioned MAT is a good alternative for the detection of presumptive Leptospira asymptomatic carrier dogs.

Serological survey of Leptospira interrogans, Toxoplasma gondii and Trypanosoma cruzi in free roaming domestic dogs and cats from a marginated rural area of Yucatan Mexico.

To evaluate the serological status for Trypanosoma cruzi, Toxoplasma gondii and Leptospira interrogans antibodies in free roaming dogs and cats from a marginated rural community in Yucatan Mexico, 100 households were visited and animals sampled. From the 106 samples, 93 were from dogs and 13 were from cats. Frequency of positive results for T. gondii, T. cruzi and Leptospira spp was 97.8%, 9.7% and 45.2% for dogs and 92.3%, 0.0% and 15.2% for cats, respectively. No associations with age, sex and body condition was found for T. gondii and Leptospira spp neither for the place where pets sleep, fumigation or presence of triatomes in the household in the case of T. cruzi. For leptospirosis the most common serovars found were Canicola, Autralis and Bratislava in dogs and cats with titres of 100 or 200 with exception of one dog with a titre of 400. The high frequency of seropositive dogs suggests a high circulation of the agents in the population of free roaming owned dogs and cats probably due to the lack of control of the reservoirs and vectors involved. Domestic animals in those rural communities can be sentinels to assess the risk of human exposure in the rural communities.

A cross sectional study of leptospirosis and fetal death in Yucatan, Mexico.

INTRODUCTION: Leptospirosis is a zoonotic disease affecting mainly to low income human population. Acute leptospiral infection during pregnancy has been associated with spontaneous abortion and fetal death during the first trimester and the abortion may occur as consequence of systemic failure. OBJECTIVE: To estimate the frequency of Leptospira interrogans infection in women with spontaneous abortion in the state of Yucatan, Mexico. METHODS: A cross sectional study on women with spontaneous abortion was conducted. Serum samples were tested for Leptospirosis by the microaglutination test, to estimate the frequency of the infecting serovar. The indirect ELISA IgM was used to detect recent infection by L. interrogans. DNA was extracted from paraffin-embedded tissue of placenta for PCR detection of L. interrogans. RESULTS: Overall frequency of infection with L. interrogans in the 81 women with abortion was 13.6%. Five of the 12 serovars evaluated were found and included. Two of the 11 women with abortion and positive to microaglutination test were also positive to the ELISA IgM test. None samples were positive for PCR Leptospira diagnosis. CONCLUSION: two women could be associated with spontaneous abortion due to leptospirosis, because they showed antibodies against L. interrogans in the microaglutination test and ELISA IgM assays. Differences between regions were found with respect to the prevalences of lesptospirosis.

INTRODUCCIÓN: Leptospirosis es una enfermedad zoonótica que afecta principalmente la población humana de bajos recursos. Infección aguda por leptospirosis durante el embarazo se ha asociado con aborto espontáneo y muerte fetal durante el primer trimestre del embarazo. OBJETIVO: Estimar la frecuencia de infección por Leptospira interrogans en mujeres con aborto espontáneo en el estado de Yucatán, México. MÉTODOS: Se efectuó un estudio transversal en 81 mujeres con aborto espontáneo. La prueba de referencia para Leptospirosis, prueba de microaglutinación, se utilizó para estimar la frecuencia de la serovar infectante. El ELISA IgM indirecto se utilizó para detectar infección reciente por L. interrogans. Se extrajo ADN a partir de tejido embebido en parafina de placenta para la detección de L. interrogans por PCR. RESULTADOS: La frecuencia global de la infección con L. interrogans en 81 mujeres con aborto, fue del 13.6%. Se encontró cinco de 12 serovares de Leptospira. Dos de las 11 mujeres con aborto espontáneo y positivo a microaglutinación también fueron positivas a la prueba ELISA IgM. Ninguna muestra fue positiva hacia el diagnóstico PCR de Leptospira. CONCLUSION: Dos mujeres podrían estar asociados con el aborto espontáneo debido a la leptospirosis, porque mostraron anticuerpos contra L. interrogans en la microaglutinación y ensayos de ELISA IgM. Diferencias entre regiones fueron encontradas con respecto a las prevalencias de leptospirosis.

A cross sectional study of leptospirosis and fetal death in Yucatan, Mexico / Estudio transversal de leptospirosis y muerte fetal en Yucatán, México

Introduction: Leptospirosis is a zoonotic disease affecting mainly to low income human population. Acute leptospiral infection during pregnancy has been associated with spontaneous abortion and fetal death during the first trimester and the abortion may occur as consequence of systemic failure. Objective: To estimate the frequency of Leptospira interrogans infection in women with spontaneous abortion in the state of Yucatan, Mexico. Methods: A cross sectional study on women with spontaneous abortion was conducted. Serum samples were tested for Leptospirosis by the microaglutination test, to estimate the frequency of the infecting serovar. The indirect ELISA IgM was used to detect recent infection by L. interrogans. DNA was extracted from paraffin-embedded tissue of placenta for PCR detection of L. interrogans. Results: Overall frequency of infection with L. interrogans in the 81 women with abortion was 13.6%. Five of the 12 serovars evaluated were found and included. Two of the 11 women with abortion and positive to microaglutination test were also positive to the ELISA IgM test. None samples were positive for PCR Leptospira diagnosis. Conclusion: two women could be associated with spontaneous abortion due to leptospirosis, because they showed antibodies against L. interrogans in the microaglutination test and ELISA IgM assays. Differences between regions were found with respect to the prevalences of lesptospirosis.

Introducción: Leptospirosis es una enfermedad zoonótica que afecta principalmente la población humana de bajos recursos. Infección aguda por leptospirosis durante el embarazo se ha asociado con aborto espontáneo y muerte fetal durante el primer trimestre del embarazo. Objetivo: Estimar la frecuencia de infección por Leptospira interrogans en mujeres con aborto espontáneo en el estado de Yucatán, México. Métodos: Se efectuó un estudio trasversal en 81 mujeres con aborto espontáneo. La prueba de referencia para Leptospirosis, prueba de microaglutinación, se utilizó para estimar la frecuencia de la serovar infectante. El ELISA IgM indirecto se utilizó para detectar infección reciente por L. interrogans. Se extrajo ADN a partir de tejido embebido en parafina de placenta para la detección de L. interrogans por PCR. Resultados: La frecuencia global de la infección con L. interrogans en 81 mujeres con aborto, fue del 13.6%. Se encontró cinco de 12 serovares de Leptospira. Dos de las 11 mujeres con aborto espontáneo y positivo a microaglutinación también fueron positivas a la prueba ELISA IgM. Ninguna muestra fue positiva hacia el diagnóstico PCR de Leptospira. Conclusion: Dos mujeres podrían estar asociados con el aborto espontáneo debido a la leptospirosis, porque mostraron anticuerpos contra L. interrogans en la microaglutinación y ensayos de ELISA IgM. Diferencias entre regiones fueron encontradas con respecto a las prevalencias de leptospirosis.

Toxoplasma gondii presence in women with spontaneous abortion in Yucatan, Mexico.

The objective of this study was to estimate the seroprevalence of anti- Toxoplasma gondii antibodies and DNA of women with spontaneous abortions in 2 hospitals located in Yucatan, Mexico. Between June 2008 and May 2009, blood samples were taken from 100 women with spontaneous abortion attending the Ticul City Communitarian Hospital and the Merida Mother-Kid Hospital. The sera were tested for anti- T. gondii IgG and IgM antibodies. Blood samples (5 ml with anticlotting agent) were also used for polymerase chain reaction (PCR) assay, to detect T. gondii DNA. Forty-two of the 100 samples were negative. Of the positive samples (n = 58), 32 were positive to IgG, 2 to IgM, 5 to IgG and IgM, 6 to IgG and PCR, 1 to IgM and PCR, and 12 to IgG, IgM, and PCR. Accordingly, 55% of the women were seropositive to at least IgG, 20% to at least IgM, and 19% via PCR. Differences between hospitals were significant (P < 0.05) only for IgM. The risk of infection (IgM positive) was 2.85 (odds ratio [OR] 95%, confidence interval [CI]; 1.03-7.87) times greater in women patients at the Merida Mother-Kid Hospital, than those at the Ticul Communitarian Hospital. More studies are needed to evaluate the impact of this disease and to establish strategies to follow in order to reduce congenital toxoplasmosis in the populations at risk.

Hemorrhagic pulmonary leptospirosis: three cases from the Yucatan peninsula, Mexico.

Three leptospirosis cases with lung involvement are reported from the Yucatan Peninsula, Mexico. All three patients were admitted to the intensive care unit due to acute respiratory failure. Treatment with antibiotics resulted in favorable evolution despite the negative prognosis. Leptospirosis should be included in the differential diagnosis of patients with fever and lung involvement.

Hemorrhagic pulmonary leptospirosis: three cases from the Yucatan peninsula, Mexico / Leptospirose hemorrágica pulmonar: três casos na península de Yucatán, México

Three leptospirosis cases with lung involvement are reported from the Yucatan Peninsula, Mexico. All three patients were admitted to the intensive care unit due to acute respiratory failure. Treatment with antibiotics resulted in favorable evolution despite the negative prognosis. Leptospirosis should be included in the differential diagnosis of patients with fever and lung involvement.

Analisamos três casos de leptospirose com envolvimento pulmonar na Península Yucatán, México. Os três pacientes com seqüelas pulmonares entraram na unidade de cuidados intensivos devido à insuficiência respiratória grave. Todos os casos evoluíram favoravelmente ao tratamento com antibióticos, apesar do prognóstico negativo. Leptospirose deve ser incluída no diagnóstico diferencial de pacientes com febre e comprometimento pulmonar.

Serological survey of canine leptospirosis in the tropics of Yucatan Mexico using two different tests.

Blood samples were taken from 400 stray dogs. The microscopic agglutination test (MAT) and enzyme-linked immunosorbent assay (ELISA) test were implemented using Leptospira interrogans serogroups canicola, hardjo, pyrogenes, panama, pomona, tarassovi, icterohaemorrhagiae, gryppotyphosa, wolffi and brastislava. For the ELISA test, sonicated antigen from above mentioned cultures was used. A conjugate AP-labeled anti-dog IgG antibody was used, the optimal cut-off point of ELISA was set at 1.34. Concordance between ELISA and MAT titers was measured by kappa (kappa). Overall prevalence was 35%. The most prevalent serogroups were canicola and icterohaemorrhagiae. Positive samples showed titers between 1:100 and 1:25,600, with higher titers found in serogroups canicola and icterohaemorrhagiae. Positive serum samples fell within a range of 1.36-1.65. A correlation index of 96% was found between MAT and ELISA. The sensitivity of ELISA was 98.6% and specificity 95.8%. Seroprevalence of canine leptospirosis and titers were high as a direct consequence of environmental conditions in the studied area. The ELISA test showed a good sensitivity, resulting in a good alternative test for the detection of leptospiral antibodies in dog serum.

Clinical-epidemiological study of leptospirosis in humans and reservoirs in Yucatan, Mexico

A leptospirosis clinical-epidemiological study was made in humans and reservoirs in the state of Yucatßn, MÚxico. Interviews and serological analyses were made on 400 persons from an open population, 439 probable cases of leptospirosis and 1060 animal reservoirs (cows, pigs, dogs, rats and opossums). IgM Leptospira DipstickTM and Microscopic Agglutination Test (MAT) was used to detect human antibodies to leptospiras and serovar respectively. Leptospirosis incidence in humans was 2.2/100,000 inhab. in 1998, 0.7/100,000 in 1999 and 0.9/100,000 in 2000. Overall seroprevalence was 14.2 percent, relatively unchanged from seroprevalences observed 20 years ago. Highest seropositivity was found in people over 56 years of age, predominating males over females. Predominant serovars in the open population were tarassovi, hardjo, pomona and panama. Leptospirosis cases were most frequent in rural areas, and the anicteric course predominated over the icteric. The panama, icterohaemorrhagiae and pomona serovars predominated in both anicteric and icteric courses. Dogs, pigs and rodents had the highest seropositivity among the reservoirs. Contact with rodents and natural water sources were significant factors (p ú 0.05). Human cases (74 percent) occurred during the rainy season. It is concluded that leptospirosis is still a serious illness with important clinical and epidemiological implications in the state of Yucatßn, Mexico

Isolation of Salmonella enterica and serologic reactivity to Leptospira interrogans in opossums (Didelphis virginiana) from Yucatán, México.

The presence of Salmonella enterica and serologic evidence of infection by Leptospira interrogans, were detected in the opossum Didelphis virginiana in a semi-urban locality of the Yucatán State, México. Ninety-one opossums were captured during the period April 1996 and May 1998. From a total of 17 feces samples, four Salmonella enterica subsp. enterica serotypes (Sandiego, Newport, Anatum, and Minnesota), and one Salmonella enterica subsp. arizonae serovar O44:Z4,Z23:- were isolated. Some opossums presented mixed infections. From 81 sera samples, four (4.9%) were positive to antibodies to Leptospira serovars pomona and wolfii. Both animals infected with Salmonella enterica and those serologically positive to Leptospira interrogans were captured in peridomestic habitat. Opossums infected with Salmonella enterica, were captured in dry season, and those seropositive to Leptospira interrogans during the rainy season. The implications of infection and reactivity of these zoonotic pathogens in D. virginiana in the Yucatan state are briefly discussed.

Isolation of Salmonella enterica and serologic reactivity to Leptospira interrogans in opossums (Didelphis virginiana) from Yucatán, México

The presence of Salmonella enterica and serologic evidence of infection by Leptospira interrogans, were detected in the opossum Didelphis virginiana in a semi-urban locality of the Yucatán State, México. Ninety-one opossums were captured during the period April 1996 and May 1998. From a total of 17 feces samples, four Salmonella enterica subsp. enterica serotypes (Sandiego, Newport, Anatum, and Minnesota), and one Salmonella enterica subsp. arizonae serovar O44:Z4,Z23:- were isolated. Some opossums presented mixed infections. From 81 sera samples, four (4.9 percent) were positive to antibodies to Leptospira serovars pomona and wolfii. Both animals infected with Salmonella enterica and those serologically positive to Leptospira interrogans were captured in peridomestic habitat. Opossums infected with Salmonella enterica, were captured in dry season, and those seropositive to Leptospira interrogans during the rainy season. The implications of infection and reactivity of these zoonotic pathogens in D. virginiana in the Yucatan state are briefly discussed

Clinical-epidemiological study of leptospirosis in humans and reservoirs in Yucatán, México.

A leptospirosis clinical-epidemiological study was made in humans and reservoirs in the state of Yucatán, México. Interviews and serological analyses were made on 400 persons from an open population, 439 probable cases of leptospirosis and 1060 animal reservoirs (cows, pigs, dogs, rats and opossums). IgM Leptospira Dipstick and Microscopic Agglutination Test (MAT) was used to detect human antibodies to leptospiras and serovar respectively. Leptospirosis incidence in humans was 2.2/100,000 inhab. in 1998, 0.7/100,000 in 1999 and 0.9/100,000 in 2000. Overall seroprevalence was 14.2%, relatively unchanged from seroprevalences observed 20 years ago. Highest seropositivity was found in people over 56 years of age, predominating males over females. Predominant serovars in the open population were tarassovi, hardjo, pomona and panama. Leptospirosis cases were most frequent in rural areas, and the anicteric course predominated over the icteric. The panama, icterohaemorrhagiae and pomona serovars predominated in both anicteric and icteric courses. Dogs, pigs and rodents had the highest seropositivity among the reservoirs. Contact with rodents and natural water sources were significant factors (p < or = 0.05). Human cases (74%) occurred during the rainy season. It is concluded that leptospirosis is still a serious illness with important clinical and epidemiological implications in the state of Yucatán, Mexico.

Leptospirosis anictérica en un brote epidémico de dengue en la Península de Yucatán / Anicteric leptospirosis in a dengue epidemic in Yucatan, Mexico

Introducción. La leptospirosis es una zoonosis de amplia distribución mundial. Posee un amplio polimorfismo clínico, pero en general se presenta en tres formas distintas: subclínica, anictérica (benigna) y grave (enfermedad de Weil). En México la información que se tiene sobre leptospirosis humana de 1970 a la fecha es escasa y en su gran mayoría proviene de estudios de corte seroepidemiológico, por lo que poco se sabe sobre sus otras formas clínicas, y tal vez por ellos sólo se relacione con la forma grave. Objetivo. Demostrar que la leptospirosis no es rara en la región y que puede estarse confundiendo clínicamente con otras entidades febriles, entre ellas el dengue. Método. Se analizaron para la búsqueda de casos de leptospirosis, sueros y expedientes clínicos de 50 pacientes que fueron diagnosticados clínicamente como dengue y que resultaron negativos en las pruebas de confirmación etiológica. Se utilizó como prueba diagnóstica la de microaglutinación (MA), utilizando como antígeno Leptospira interrogans vivas de ocho serovares diferentes. Resultados. Se encontraron siete pacientes positivos a leptospirosis (14 por ciento). La sintomatología que presentaron correspondió a la descrita para la forma anictérica. Tres fueron de Yucatán y cuatro de Campeche. En el primer Estado predominó el serovar canícola y en el segundo el serovar pomona. Conclusiones. La leptospirosis es una enfermedad infecciosa presente al igual que el dengue en los estados de Yucatán y Campeche, por lo que se le debe tomar en cuenta en el diagnóstico diferencial, sobre todo en zonas geográficas en donde los dos padecimientos son endémicos