Triclabendazole efficacy, prevalence, and re-infection of Fasciola hepatica in bovine and ovine naturally infected in the Andes of Ecuador.

Fasciola spp., infections are distributed worldwide including the Andes region of Ecuador, affecting cattle, sheep, porcine, humans, and other herbivores. Triclabendazole (TCBZ) is commonly used to treat animal infections. However, prospective studies on TCBZ efficacy and fascioliosis prevalence have not been studied in the highlands of Ecuador. This study was performed in a rural community at central of the Ecuadorian Andes in freely roaming bovine and ovine aimed to 1) evaluate the efficacy of TCBZ by administering a single oral dose of 12 mg/kg body weight, 2) assess the prevalence of F. hepatica infection and 3) to monitor re-infections for a follow-up period of five months. In total, 122, 86, 111, 110, 89, and 90 and 49, 34, 47, 28, 27, and 31 stool samples were collected each month from bovines and ovine, respectively. Besides, 32 stool samples from porcine were also collected at the beginning of the study. Stools were microscopically analyzed by formalin-ether concentration method to detect F. hepatica ova. The prevalence of F. hepatica infections before treatment was 55,7% and 63,3% for bovine and ovine, respectively. The infection prevalence was of 22% in porcine. The efficacity of triclabendazole was 83% and 97% in bovines and ovine, respectively, at 30 days post-treatment. The re-infection reaches to 54,4% in bovines and 61,3% in ovine after five months. TCBZ had a high efficacy and could be used for bovines and ovine Fasciola infections in the study region; however, re-infections reach the initial prevalence after five months. Therefore, we recommend integrated control strategies, including chemotherapy with a single oral dose of TCBZ, vector control, and future drug resistance studies.

Safety, immunogenecity, and efficacy of an autoclaved Leishmania amazonensis vaccine plus BCG adjuvant against New World cutaneous leishmaniasis.

The safety, immunogenecity, and efficacy of two doses of an autoclaved-killed, whole cell Leishmania amazonensis vaccine (IFLA/BR/67/PH8) and BCG adjuvant (n = 750) against cutaneous leishmaniasis (CL) was compared with placebo (n = 756) in a randomized, placebo-controlled, blinded study. Systemic and local side-effects were more frequent in the vaccine than placebo group. Leishmanin skin test (LST) conversion was greater in the vaccine than placebo group 2 months after the second vaccination dose (74.4% versus 14.7%; P = 0.000001). The 26-month incidence of confirmed CL (n = 25) was similar between the vaccine (2.0%) and placebo groups (2.0% versus 1.3%; P > 0.05). LST conversion was not associated with CL protection and the vaccine did not offer significant protection against CL infection caused by L. Viannia spp. compared to placebo.

Usefulness of sampling with cotton swab for PCR-diagnosis of cutaneous leishmaniasis in the New World.

In this study, we tested the polymerase chain reaction (PCR)-method to diagnose cutaneous leishmaniasis (CL) by taking exudate materials from lesions with cotton swabs, using our previously tested (PCR) panel comprised of Leishmania (Viannia) panamensis, L. (V.) braziliensis, L. (V.) guyanensis, L. (Leishmania) mexicana and L. (L.) amazonensis. The objectives of the present study were to improve the sampling method convenient for the patients and to test the usefulness of samples taken with cotton swabs. Sixteen patients were clinically diagnosed to have CL including one case of diffuse cutaneous leishmaniasis (DCL) in Ecuador and the causative Leishmania parasites were identified by PCR. All the 12 samples from CL patients of La Mana, positive for Leishmania DNA, were identified as L. (V.) panamensis, while two from CL of Huigra and one from DCL of San Ignacio were L. (L.) mexicana. In the field condition, taking biopsy material is not only painful but sometimes causes iatrogenic bacterial infections. Considering the sensitivity of the test, and convenient sampling procedure, it may be suggested that collection of exudates using cotton swabs may be a better alternative to biopsy sample for PCR-diagnosis of CL.

Treatment of human pulmonary paragonimiasis with triclabendazole: clinical tolerance and drug efficacy.

An open clinical trial to determine the efficacy and tolerability of postprandial doses of triclabendazole against Paragonimus mexicanus in 62 patients with pulmonary paragonimiasis from the Ecuadorian Amazon region was performed. Praziquantel was used as therapeutic control. Patients were allocated at random to the following 4 therapeutic regimens: triclabendazole, 5 mg/kg once daily for 3 d (16 patients), 10 mg/kg twice on one day (15 patients), and 10 mg/kg in a single dose (16 patients), and praziquantel, 25 mg/kg thrice daily for 3 d (15 patients). Clinical tolerance, based on the frequency and severity of adverse reactions, was superior in all 3 triclabendazole regimens to that of praziquantel. No alteration was observed in hepato-renal functions or haematological values. The clinical symptoms resolved at a comparable rate in all 4 treatment groups. A more rapid parasitological response to treatment, as determined by the reduction in the average number of parasite eggs found in sputum, was seen in patients treated with triclabendazole than with praziquantel. By day 90, 60 patients had no egg detected in their sputum; 2 patients, treated with a single dose of 10 mg/kg, had a few and were re-treated with triclabendazole (5 mg daily for 3 d). On day 365, none of the patients had eggs in their sputum. Triclabendazole can be recommended as an alternative drug of choice for the treatment of pulmonary paragonimiasis; it is as effective as praziquantel in clearing infections and better tolerated.

Chagas disease in Ecuador: evidence for disease transmission in an Indigenous population in the Amazon region.

Two well-defined synthetic peptides TcD and PEP2 were used in a sero-epidemiological study for the detection of Trypanosoma cruzi infections in an indigenous group in the Amazon region of Ecuador. Of the 18 communities studied along the Rio Napo, province of Napo, 15 (83.3%) were found to be positive for T. cruzi infection. Of the 1,011 individuals examined 61 (6.03%) resulted positive. A prevalence of infection of 4.8% was found in children aged 1-5 years. The prevalence of infection increased with age, with adults 50 years or older showing a maximum prevalence of 18.8%. Autochthonous transmission of T. cruzi is present among this isolated indigenous population.

An outbreak of bartonellosis in Zamora Chinchipe Province in Ecuador.

We report an outbreak of human bartonellosis in Zamora Chinchipe Province in Ecuador, which occurred in 1995-1996. Nineteen cases were seen, of which 18 presented with classical oroya fever (fever and profound anaemia) and one with verruga peruana; 11 of the cases (58%) had positive blood films containing Bartonella bacilliformis. The houses of cases and neighbouring controls were visited; blood samples for thin films and cultures were collected from members of each house and a questionnaire was administered to investigate possible risk factors for disease transmission. In none of those sampled was B. bacilliformis bacteriologically demonstrable. All case houses were located in isolated areas at the margin of forest and the presence of dead rodents was reported only in case houses (P < 0.05). We suggest that human bartonellosis is a zoonosis with a natural rodent reservoir and that migrant humans infected in this way may become a temporary reservoir host in populated areas.

In utero exposure to Onchocerca volvulus: relationship to subsequent infection intensity and cellular immune responsiveness.

Afro-Ecuadorian individuals from an area where Onchocerca volvulus is hyperendemic have been monitored for infection over the past 16 years. To determine whether in utero exposure to O. volvulus biases a child's subsequent immune responses, children (9 to 16 years old) for whom the mother's infection status was known were chosen for study. Children of infected mothers (n = 19) had significantly higher levels of skin microfilariae than children of uninfected mothers (n = 13; P = 0.021). While the serum levels of O. volvulus-specific immunoglobulin G (IgG), IgG subclasses, and IgE showed no significant differences between the two groups of children, peripheral blood mononuclear cells of children of infected mothers produced higher levels of Th2-type cytokines to several parasite antigens and lower levels of Th1-type cytokines to nonparasite antigens than those of children of uninfected mothers. Thus, in utero exposure to O. volvulus has a long-term effect on the child's subsequent cellular immune response that may render the child more susceptible to O. volvulus infection postnatally.

Resistance to Onchocerca volvulus: differential cellular and humoral responses to a recombinant antigen, OvMBP20/11.

Persons putatively immune (PI) to Onchocerca volvulus (Ov) infection were identified in Ecuador on the basis of epidemiologic, clinical, and parasitologic findings. Immune responses of PI subjects to a recombinant onchocercal protein, OvMBP20/11, were determined and compared with those of a comparable infected (INF) group from the same Ov-endemic area. PI subjects had significantly less antibody reactivity to this molecule; however, not all INF subjects had an antibody response. IgG1 and IgG4 were the predominant IgG subclasses induced to this molecule, and the amount of IgG1 produced was the only significant difference between the PI and INF groups. In contrast to the antibody responses, proliferative responses to OvMBP20/11 were significantly higher in PI than in INF subjects. Cytokine analysis of peripheral blood mononuclear cell culture supernatants revealed that INF subjects produced significantly more interleukin-10 in response to OvMBP20/11 than did PI subjects. This antigen induced few other cytokines, and there were no differences between study groups.

Antibody isotypes, including IgG subclasses, in Ecuadorian patients with pulmonary paragonimiasis.

An ELISA test was developed to detect Paragonimus-specific antibodies, including IgG subclasses, using P. mexicanus crude water-soluble antigens. The test was standardized to detect antibodies in sera of Ecuadorian patients with pulmonary paragonimiasis and negative controls from the endemic area. The detected mean levels of IgG (0.753, SEM: 0.074) and IgM (0.303, SEM: 0.033) were significantly elevated (P < 0.05). Within the IgG subclasses, IgG4 showed the highest detected mean level (0.365, SEM: 0.116) and the other three subclasses showed considerably lower mean levels (IgG1, 0.186 SEM: 0.06; IgG2, 0.046 SEM: 0.01; IgG3, 0.123 SEM: 0.047). The number of P. mexicanus eggs found in sputum of infected individuals showed a positive correlation with the level of antibodies detected for IgM, IgG and its subclasses (P < 0.001). The relevance of these findings in Ecuadorian patients suffering from pulmonary paragonimiasis is discussed.

Immunity to onchocerciasis: putative immune persons produce a Th1-like response to Onchocerca volvulus.

Immunity to Onchocerca volvulus (Ov) infection is suggested by the presence of putatively immune (PI) subjects in a region of Ecuador in which Ov is endemic. PI subjects were identified by traditional diagnostic methods combined with a polymerase chain reaction-based assay for Ov DNA in skin snips. Responses of peripheral blood mononuclear cells (PBMC) from the PI group (n = 16) were compared with those of persons with active infection (microfiladermic [MF] subjects; n = 51). PBMC of PI subjects proliferated significantly more to Ov antigen (OvAg; P < .009) than did PBMC of MF persons but less to streptolysin-O (P < .001). Cytokine analysis of PBMC culture supernatants revealed that PI subjects (n = 11) produced significantly more interferon-gamma to OvAg than did those in the MF group (n = 18; P = .018), less interleukin (IL)-5 to nonparasite antigen (P = .003) and mitogen (P = .012), and less IL-10 spontaneously (P = .016). Thus, immunity to Ov may in part be mediated by an antigen-specific Th1-type response.

Studies on a focus of yaws in the Santiago Basin, province of Esmeraldas, Ecuador.

A clinical and serological epidemiological study done on a yaws focus in the Santiago Basin area, province of Esmeraldas, showed a prevalence of 11.3% for active clinical lesions and a seropositivity of 94.9%. The Rio Santiago was hyperendemic for yaws (prevalence, 17.9%; seropositivity, 98.0%) while Rio Zapallito was found to be mesoendemic and the Rio Cayapas and Rio Onzoles hypoendemic. Active and latent evidence of yaws was found only in the black race. Children, ages 5-12 year, were found to have the highest incidence (55.8%) of clinical lesions, with the majority found on the legs (64.2%). Papilloma was the most prevalent lesion (55.4%). Mass treatment of the basin using benzathine penicillin G was done according to WHO recommendation.