An Unexpected Case of Lagochilascariasis: Interdisciplinary Management and Use of 12S and 18S rDNA Analysis.

A Mexican 24-year-old male patient was referred to our hospital due to increased left retroauricular volume with skin fistulisation, resembling an infection by the uncommon worm Lagochilascaris minor. The patient was submitted to lateral skull base surgery. No adult worms or eggs were observed during light and scanning electron microscopy analysis, as well as by histopathologic examination of the small piece of removed tissue, only L3 stage larvae of Lagochilascaris spp. were identified. Polymerase chain reaction-sequencing assays were performed using primers for the mitochondrial 12S and the nuclear 18S rDNA gene. DNA of some L minor adults, previously identified, were used as control. The molecular analysis identified the worm as L minor. According to previous reports, lagochilascariasis is a complicated infection that requires an interdisciplinary management by different clinical specialists. This is the first time that 12S and 18S rDNA genes are reported as molecular markers for diagnosis of L minor.

Diagnosis of Congenital Chagas Disease Using an Iron Superoxide Dismutase Excreted as Antigen, in Mothers and Their Children During the First Year of Life.

BACKGROUND: Chagas disease caused by Trypanosoma cruzi is endemic in Latin America. Human infection is mainly spread by Triatominae insects. Other forms of transmission are congenital, blood transfusion and organ transplantation. METHODS: Anti-T. cruzi antibodies were determined by enzyme-linked immunosorbent assay (ELISA) and Western blot (WB) in 155 serum samples from mothers and their babies. Indirect immunofluorescence (IFA) and a commercial test were used to validate efficacy of a specific ELISA-iron-excreted superoxide dismutase assay. Sera from babies were collected at 6 and 12 months, whereas maternal samples were obtained after delivery. Calostrum and umbilical cord samples were simultaneously obtained. RESULTS: Anti-T. cruzi antibodies were detected in 8 (5.16%) mothers by ELISA-WB, in 7 (4.51%) using IFA and in 1 (0.64%) by a commercial kit. Nine (5.80%) 6-month-old children were positive by ELISA-WB and 7 (4.51%) by IFA; negative results were obtained when the commercial kit was used. At 12 month of age, 15 (9.67%) children were positive by ELISA-WB, 13 (8.38%) by IFA and 1 (0.64%) by the commercial test. Antibodies were detected in 4 mothers whose children were serologically negative. Four other mothers and their children were positive, but only one of them had detected antibodies in umbilical cord up to 12 months, thus assuming vertical transmission. CONCLUSIONS: The use of iron-excreted superoxide dismutase as antigen in serologic tests for detection of T. cruzi yielded promising results as diagnostic procedure.

Lagochilascaris minor Leiper, 1909 (Nematoda: Ascarididae) in Mexico: three clinical cases from the Peninsula of Yucatan / Lagochilascaris minor Leiper, 1909 (Nematoda: Ascarididae) en México: tres casos clínicos de la Península de Yucatán

Human lagochilascariasis (HL) is a parasite produced by Lagochilascaris minor Leiper 1909 that also can be found in cats and dogs. HL is considered an emerging zoonosis in the Americas, spreading from Mexico to Argentina, and the Caribbean Islands. The present paper describes three HL cases from the Peninsula of Yucatan, Mexico, recorded in the last decade. It describes the characteristics of the lesions and discusses the route of transmission in humans and particularly in the observed patients.

La Lagochilascariasis humana (HL) es producida por Lagochilascaris minor Leiper, 1909; el cual es un parásito que puede ser encontrado también en gatos y perros. HL es considerada una zoonosis emergente en América distribuida desde México hasta Argentina y las islas del Caribe. El presente artículo describe tres casos de HL en la Península de Yucatán, México registrados en la última década. Se describen las características de las lesiones y se discute la ruta de transmisión en humanos y particularmente en los pacientes observados.

Lagochilascaris minor Leiper, 1909 (Nematoda: Ascarididae) in Mexico: three clinical cases from the Peninsula of Yucatan.

Human lagochilascariasis (HL) is a parasite produced by Lagochilascaris minor Leiper 1909 that also can be found in cats and dogs. HL is considered an emerging zoonosis in the Americas, spreading from Mexico to Argentina, and the Caribbean Islands. The present paper describes three HL cases from the Peninsula of Yucatan, Mexico, recorded in the last decade. It describes the characteristics of the lesions and discusses the route of transmission in humans and particularly in the observed patients.

An iron-superoxide dismutase antigen-based serological screening of dogs indicates their potential role in the transmission of cutaneous leishmaniasis and trypanosomiasis in Yucatan, Mexico.

An increasing number of studies have reported high infection rates for American cutaneous leishmaniasis in dogs, which have thus been proposed as the reservoir host. Canine leishmaniasis is widespread in different states in Mexico, where a number of Leishmania species have been isolated from dogs. In the present study, the detection of different Leishmania species is described in stray dogs from two localities, namely Tulum and Celestún on the Yucatan Peninsula (Mexico). The use of iron-superoxide dismutase excreted by the parasites as the antigen fraction and enzyme-linked immunosorbent assay and western blot tests allowed us to confirm the presence of at least three species of Leishmania (Le. mexicana, Le. braziliensis, and Le. panamensis), some of which are reported for the first time in this species. In addition to a high prevalence of Le. mexicana and Le. braziliensis, and to a lesser degree, Le. panamensis, there is a significant prevalence of Trypanosoma cruzi, suggesting that the dog may be a source of transmission of trypanosomiasis. However, a more thorough epidemiological study on the dog population, both wild as well as urban, of the Yucatan Peninsula will be required to design a control strategy for these diseases, paying particular attention to the population affected and even broadening the study to other Mexican states as well as neighboring countries. These results again confirm that iron-superoxide dismutase excreted by the different trypanosomatid species constitutes a good source of antigen for serodiagnosis in epidemiological studies.

Abundance and nightly activity behavior of a sylvan population of Triatoma dimidiata (Hemiptera: Reduviidae: Triatominae) from the Yucatan, México.

Triatoma dimidiata is the vector of Trypanosoma cruzi in the Yucatan Peninsula (YP). Earlier studies have shown that domestic and peri-domestic populations of the vector originated from the sylvan stock and that effectiveness of insecticide-spraying was affected by re-infestations of houses from the sylvan T. dimidiata population. In addition, in the YP most previously published reports have focused on domestic and peri-domestic populations and very little is known about the nocturnal behavior of the sylvan populations. The main aim of our study was to determine the nightly activity patterns of adult T. dimidiata in a selected location in the YP. Secondly, we sought to document the reproductive status and infection rate of active females. During eight sampling nights spaced from late March to late July, 2007, we collected 544 adult T. dimidiata. We found that square-cloth illuminated white traps were effective to attract the sylvan individuals and that T. dimidiata adults exhibited a unimodal activity pattern throughout the night. The accumulated mean of captured bugs also showed a non-linear distribution for females and males. Furthermore, we found that male and female catches were significantly correlated with the means of temperature and humidity recorded during the sampling period. Out of 46 dissected females, we observed that 43.5% of females had fully-formed eggs in their abdomens, and only two females (4.4%) had sperm within the spermatheca. The infection rate of T. dimidiata harboring T. cruzi was found to be 3.7%. The implications of the light attraction to bugs and potential dispersal capabilities are discussed in the paper in the context of infestation/re-infestation of rural houses by sylvan T. dimidiata flying adults.

Comparative evaluation of therapeutic DNA vaccines against Trypanosoma cruzi in mice.

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, is a major public health problem in most of Latin America. A key priority is the development of new treatments, due to the poor efficacy of current ones. We report here the comparative evaluation of therapeutic DNA vaccines encoding various T. cruzi antigens. ICR mice infected with 500 parasites intraperitoneally were treated at 5 and 12 days postinfection with 20 microg of plasmid DNA encoding T. cruzi antigens TSA-1, TS, ASP-2-like, Tc52 or Tc24. Treatment with plasmid encoding TS and/or ASP-2-like antigens had no significant effect on parasitemia or survival. Treatment with Tc52 DNA significantly reduced parasitemia, as well as cardiac parasite burden, and improved survival, although myocarditis was not significantly affected. Finally, treatment with plasmids encoding Tc24 and TSA-1 induced the most complete control of disease as evidenced by significant reductions in parasitemia, mortality, myocarditis and heart parasite burden. These data demonstrate that therapeutic vaccine efficacy is dependent on the antigen and suggest that DNA vaccines encoding Tc24, TSA-1, and Tc52 represent the best candidates for further studies of a therapeutic vaccine against Chagas disease.

Control of Trypanosoma cruzi infection and changes in T-cell populations induced by a therapeutic DNA vaccine in mice.

Previous work showed that immunotherapy with a DNA vaccine encoding Trypanosoma cruzi antigen TSA-1 reduced cardiac tissue damage and improved survival in mice when administered during the acute or chronic phases of T. cruzi infection. In the present study, we investigated changes in T-cell populations induced by DNA vaccine immunotherapy. ICR mice were infected with 500 T. cruzi blood trypomastigotes and treated during the acute or chronic phases with two 100 microg doses of DNA vaccine. Analysis of stained splenocytes by flow cytometry indicated that the therapeutic vaccine induced a rapid increase in the number of CD4+ and CD8+ T cells in both the acute and chronic phases. Also, there was a rapid increase in T. cruzi-specific IFNgamma-producing CD8+ T cells following treatment during the chronic phase. The effects of these changes on the control of infection required longer time periods to be detectable but resulted in a reduction in myocarditis and T. cruzi parasite burden in both phases of the infection, as assessed by histopathologic analysis and semi-quantitative PCR detection of T. cruzi in cardiac tissue. These results suggest that DNA vaccines that induce CD8+ T-cells activity and IFNgamma production, would be good candidates for effective therapeutic vaccination against T. cruzi infection.

Effect of Hurricane Isidore on Triatoma dimidiata distribution and Chagas disease transmission risk in the Yucatán Peninsula of Mexico.

Hurricanes can have devastating effects on health and may directly modulate vector-borne diseases. Chagas disease is a zoonosis caused by the protozoan parasite Trypanosoma cruzi and transmitted by triatomine bugs, and the effect of hurricanes on these bugs is largely unknown. We thus performed a detailed study of the changes in Triatoma dimidiata geographic distribution and infection rates after Hurricane Isidore devastated the Yucatán Peninsula in September 2002. Bugs were collected in 34 villages from the entire peninsula, during a year, starting 3 months after the hurricane. Pre- and posthurricane bug collections were compared to assess changes. The most notable effect was a large increase in domestic abundance of T. dimidiata during the 6 months after the hurricane. This increase was maximum along the path of the hurricane. These results suggest that vector control programs should be implemented along the path of hurricanes to prevent an increase in Chagas disease transmission risk in the ensuing months.

Immunotherapy of Trypanosoma cruzi infection with DNA vaccines in mice.

The mechanisms involved in the pathology of chronic chagasic cardiomyopathy are still debated, and the controversy has interfered with the development of new treatments and vaccines. Because of the potential of DNA vaccines for immunotherapy of chronic and infectious diseases, we tested if DNA vaccines could control an ongoing Trypanosoma cruzi infection. BALB/c mice were infected with a lethal dose (5 x 10(4) parasites) as a model of acute infection, and then they were treated with two injections of 100 microg of plasmid DNA 1 week apart, beginning on day 5 postinfection. Control mice had high levels of parasitemia and mortality and severe cardiac inflammation, while mice treated with plasmid DNA encoding trypomastigote surface antigen 1 or Tc24 had reduced parasitemia and mild cardiac inflammation and >70% survived the infection. The efficacy of the immunotherapy also was significant when it was delayed until days 10 and 15 after infection. Parasitological analysis of cardiac tissue of surviving mice indicated that most mice still contained detectable parasite kinetoplast DNA but fewer mice contained live parasites, suggesting that there was efficient but not complete parasite elimination. DNA vaccine immunotherapy was also evaluated in CD1 mice infected with a low dose (5 x 10(2) parasites) as a model of chronic infection. Immunotherapy was initiated on day 70 postinfection and resulted in improved survival and reduced cardiac tissue inflammation. These results suggest that DNA vaccines have strong potential for the immunotherapy of T. cruzi infection and may provide new alternatives for the control of Chagas' disease.