SUMMARYA 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 ≤ 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.

No abstract

SUMMARYThe 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. KEYWORDS: Didelphis virginiana; Salmonella enterica; Leptospira interrogans; Yucatán; México.Opossums of the genus Didelphis have been frequently found infected with several zoonotic diseases 7 . Didelphis virginiana occurs widely in México including the Yucatán Peninsula where this opossum is abundant in the peridomestic habitat, thus bringing a risk to transmit zoonotic diseases such as Chagas disease to the human populations 8 . In this paper, we report for the first time in México data on the infection by Salmonella enterica and the seroprevalence of antibodies against Leptospira interrogans in D. virginiana. This information constitutes a contribution to the knowledge of the epidemiology of zoonotic diseases in México, where in spite the abundance of this mammal in peridomestic habitat, its role in the epidemiology of many zoonotic diseases has not been evaluated.The data of infection by S. enterica and L. interrogans in opossum, were obtained during a populational study of this mammal to evaluate its importance as a reservoir of Trypanosoma cruzi, the etiologic agent of Chagas disease 8 . Opossums were captured from April 1996 to May 1998 in Dzidzilché (21°08'51.76" and 89°41'28.24"), a semiurban small village located 25 km northwestern Mérida, the capital of the Yucatán State, México (Fig. 1). Thorny and low forest, and scarce remains of low deciduous forest characterized the vegetation of the study area. Many abandoned sisal fields doted the surroundings of the village. Fruit trees such as Mangifera inca (mango), Manilkara achras (gumtree), Spondias purpurea (plum), Citrus aurantium (orange), and Carica papaya (papaya), were common in the courtyards. The climate was predominantly warm and humid, with a mean annual temperature of 25.4 °C. During the study period, the rainy season ranged from June to October, and the average annual rainfall was 449 mm.The capture of opossums was carried out following the capture-markingrecapture scheme in a grid of 4 x 4 Tom...

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.

In the state of Yucatan, Mexico, rickettsiosis has become a common vector-borne disease in the general population. Ectoparasite species such as Rhipicephalus sanguineus and Amblyomma mixtum have been identified as Rickettsia vectors in Yucatan by studies focused on the wild animal population in rural areas. There have been studies that have tried to determine the presence of Rickettsia species in ectoparasites collected in Yucatan, but these studies did not include marginalized areas, where living in close contact with domestic and peridomestic animals that carry ectoparasites is a high-risk factor for acquiring rickettsial infection or many other vector-borne diseases. We evaluated the vector diversity and the presence of Rickettsia species presence in the ectoparasite population that parasitizes domestic animals in a marginalized rural town of Yucatan, Mexico; we also evaluated the seroprevalence of rickettsial antibodies in the human population of this town in order to determine the prevalence of rickettsial infection. A total of 437 ectoparasites were collected from the study area. The tick specimens collected belonged to the species Rhipicephalus sanguineus (n=380, 49 positive), Amblyomma mixtum (n=3, 0 positive), Ixodes affinis (n=4, 0 positive), Ctenocephalides felis (n=33, 0 positive), and Trichodectes canis (n=17, 0 positive). Conventional polymerase chain reaction and sequencing were used to identify the DNA of Rickettsia. Six out of 354 (1.8%) serum samples were positive for antibody to R. typhi. The combination of low antibody titers and the presence of Rickettsia species infecting ectoparasite species found in the study area requires eco-epidemiological studies and the identification of potentially protective practices or habits.

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.

Introducción. El Síndrome Pulmonar por Hantavirus (SPH) es una zoonosis emergente en el continente Americano, caracterizado por un estado febril y rápida aparición de edema pulmonar con letalidad ›40%. Es ocasionada por un virus de la familia Bunyaviridae; sus principales reservorios son roedores de la subfamilia Sigmodontinae. El propósito de este trabajo fue detectar la presencia de anticuerpos contra Hantavirus en muestras de suero humano y mamíferos silvestres y sinantrópicos en el estado de Yucatán. Material y Métodos. Se analizaron 616 muestras de suero humano provenientes de población abierta y 92 muestras de roedores mediante la técnica de ELISA indirecta para la detección de anticuerpos contra Hantavirus. Resultados. Se demostró la presencia de anticuerpos contra Hantavirus en cuatro muestras de humanos (0.6%), con títulos de 1/320 a › 1/20,000; el rango de edad de las personas seropositivas fluctuó entre 2.4 a 80 años. Sin embargo, los sueros de los roedores fueron negativos. Conclusión. La identificación de personas seropositivas a Hantavirus es la primera evidencia de que un virus cercano a los que ocasionan el SPH, está circulando en el Estado 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.