Efficacy of a Zn-based metalorganic framework doped with benznidazole on acute experimental Trypanosoma cruzi infection.

Metal-Organic Frameworks (MOFs) have been shown to enhance the activity of encapsulated compounds by facilitating their passage across cell membranes, thereby enabling controlled and selective release. This study investigates the efficacy of BNZ@Zn-MOFs against the acute phase of Trypanosoma cruzi infection in a mouse model. The particles were synthesized by electroelution (EL), doped with BZN via mechanochemistry, and characterized using scanning electron microscopy (SEM), infrared spectroscopy (FTIR), and X-ray diffraction (XRD). BNZ@Zn-MOFs released 80% of the encapsulated BZN within 3 h, demonstrating no cytotoxicity in NIH-3T3 and HeLa cells. Furthermore, in a model of acute experimental T. cruzi-infection in BALB/c mice, the delivery system exhibited antiparasitic activity at a significantly lower BZN concentration compared to free BZN treatment. PCR analysis of treated mice revealed no parasite DNA in their tissues, and hematoxylin-eosin staining showed no apparent damage to tissue architecture. Additionally, serum levels of liver function enzymes remained unchanged, indicating no adverse effects on liver function. This delivery system, utilizing suboptimal BZN doses, enables the preservation of drug activity while potentially facilitating a substantial decrease in side effects associated with Chagas disease treatment.

Circadian Variation of Immune Cell Populations in Preterm Human Milk: A Preliminary Study.

Introduction: Breast milk contains both nutritional and non-nutritional components for the newborn, with some of the latter exhibiting marked diurnal variations in concentration. This study aimed to analyze the circadian behavior of specific immune cell populations and proinflammatory cytokines present in the transitional milk of premature infants. Methods: The study quantified cellular components, including stem and immune cells, using flow cytometry. Additionally, ELISA assays were employed to measure proinflammatory cytokine concentrations. Results: Flow cytometry analyses revealed a diurnal rise in the percentage of CD23+, CD32+, CD36+, CD2+, and Tγδ cell populations. Conversely, nocturnal increases were observed in the percentage of CD16+, CD19+, and CD4+ populations. Notably, CD3+ and CD8+ populations did not exhibit any rhythmic variations. Proinflammatory cytokine concentrations were found to be higher in daytime milk samples compared to those collected at night. Conclusion: This study demonstrates rhythmic fluctuations in both immune cell populations and proinflammatory cytokine concentrations within the transitional milk of premature mothers.

Pfizer-BioNTech vaccine induces the production of cross-reactive antibodies against Trypanosoma cruzi proteins: A preliminary study.

OBJECTIVE: To evaluate the presence of cross-reactivity by anti-severe acute respiratory syndrome coronavirus 2 antibodies induced by the Pfizer-BioNTech vaccine against Trypanosoma cruzi proteins in a screening test. METHODS: Forty-three serum samples were obtained from personnel at the Hospital General Naval de Alta Especialidad in Mexico City who received one or two doses of the vaccine and were tested for T. cruzi infection using four tests: two 'in house' enzyme-linked immunosorbent assays (ELISAs), a commercial ELISA diagnostic kit and an immunoblot test. RESULTS: IgG antibodies against the T. cruzi proteins were present in the serum of unvaccinated subjects and subjects who had received one or two doses of the vaccine. The positivity of the samples against T. cruzi was ruled out by means of a Western Blot assay, where all samples were negative for T. cruzi. CONCLUSION: The data suggest that people convalescing from coronavirus disease 2019 and those who received the Pfizer-BioNTech vaccine exhibit cross-reactive antibodies against T. cruzi antigens in ELISA assays.

Identification of a triatomine infected with Trypanosoma cruzi in an urban area of the state of Veracruz, Mexico: A comprehensive study.

Chagas disease, considered a neglected disease, was initially confined to rural localities in endemic areas; however, in recent years through the process of urbanization and migration of infected people, the disease is gaining importance in urban environments. The presence of the vector in urban areas in most cases is due to the passive transport of vectors, but recently, its presence seems to be linked to vector adaptation processes associated with climate change. This paper reports the occurrence of an infected triatomine in the peridomicile of a house in an urban area of Córdoba, Veracruz, Mexico, where the species found is described, the molecular characteristics and resistance to BZN and NFX of the Trypanosoma cruzi isolate obtained, as well as serological data of the dwelling inhabitants. These urban disease scenarios make it possible to generate new scientific knowledge and enable the creation of new control strategies for Chagas disease vectors.

Effect of immunosuppression by UV-B radiation on components of the innate immune response in skin lesions with Leishmania mexicana: Effect of UVB on the innate immune response in cutaneous infection by L. mexicana.

Cutaneous leishmaniasis is the most common form of leishmaniasis in humans, factors such as poverty, poor housing, inadequate domestic hygiene, malnutrition, mobility, and occupational exposure are risk factors associated with the condition, however, there are few studies focused on determining the immune mechanism involved in the resolution of cutaneous leishmaniasis caused by the species Leishmania mexicana, as well as possible environmental factors such as solar radiation, which could contribute to its establishment. through mechanisms immunosuppressants, of which to date is unknown. In this study, the effect of UV-B light was evaluated as a risk factor affecting components of the innate immune response 3 days after infection with L. mexicana. A delayed-type hypersensitivity reaction (DTH) was used to evaluate immunosuppression induced by UV-B light. Through a histological analysis, the skin lesions of the mice (Hematoxylin & Eosin) were evaluated, the presence of mast cells and their level of degranulation (toluidine blue staining), the presence of IL-10+ and MOMA2+ cells were analyzed by immunohistochemistry and finally, the cytokine profile was evaluated by qPCR in the skin lesions tissue. An alteration in the architecture of the tissue was observed, as well as a greater number of mast cells, both complete and degranulated, as well as an increase in IL-10+ and MOMA2+ cells in the skin lesions of the mice that were irradiated and subsequently infected, when compared with the lesions of infected mice (P> 0.0001), immunomodulation was also observed in the profile of cytokines expressed between both groups analyzed. This is the first study to demonstrate the effects of UV-B radiation on components of the innate immune response at short times of infection by L. mexicana.

Diversity of Trypanosoma cruzi parasites infecting Triatoma dimidiata in Central Veracruz, Mexico, and their One Health ecological interactions.

Triatoma dimidiata is the main vector of Trypanosoma cruzi parasites in Veracruz, Mexico, and its association with human housing appears variable. Also, in spite of a high seroprevalence of T. cruzi infection in humans, parasite transmission remains poorly understood. Therefore, we aimed to identify T. dimidiata blood feeding sources and its parasite and microbial diversity to reconstruct T. cruzi parasite transmission ecology in central Veracruz, Mexico, within a One Health/Ecohealth framework. We used a metabarcoding and deep sequencing approach of specific markers for the simultaneous identification of T. dimidiata haplogroup (ITS-2), vertebrate blood meals (12 s gene), T. cruzi parasites (mini-exon gene), and gut microbiota (bacterial 16 s). Twelve species of domestic/synanthropic animals and humans were identified as blood sources, with multiple feeding on 4.2 ± 0.4 hosts per bug. The feeding/parasite transmission network was strongly centered on humans, emphasizing a significant risk of infection. We also unambiguously confirmed the presence of TcI, TcII, TcV and TcVI DTUs in T. dimidiata, and sequences from Veracruz tended to cluster apart from parasites from other regions, suggesting some level of local differentiation. Analysis of T. dimidiata microbiota suggested that several bacterial families may be associated with the presence/absence of T. cruzi, and some of these associations may also be parasite DTU-specific. Such integrative approaches within the EcoHealth/One Health framework provide key insights on T. cruzi transmission and potential novel strategies for disease control.

Risk factors for infestation by Triatoma dimidiata in a rural locality of Veracruz, Mexico, with active transmission of Trypanosoma cruzi: weather and rain as factors.

OBJECTIVE: To analyse the ecological and social factors involved in infestation of houses by Triatoma dimidiata in a rural locality of Veracruz, Mexico, where active transmission of the parasite is occurring. METHODS: A survey was applied to the households of the locality to obtain sociodemographic data. In parallel, T. dimidiata insects were collected during one year through community participation. Using PCR, the insects were genotyped, their infection status was assessed, and parasite genotypes infecting the insects were identified. The vector's blood meal sources were identified using a polymerase-heteroduplex chain reaction assay. RESULTS: Seasonal variations in the patterns of infestation by T. dimidiata were observed. An overall infestation rate of 19.46%, a colonisation index of 9.09%, a dispersion rate of 22.15% and a synanthropy index of 80.6% were found. The collected insects were identified as ITS-2 group 2 insects, and a natural infection with T. cruzi of 54.35% was found. TcI and no-TcI genotypes of T. cruzi were found in infected insects. Factors such as rain (P = 0.0006) and temperature (P < 0.0001) were associated with infestation. Analysis of the blood meal sources indicated frequent feeding upon humans and mice. Furthermore, house materials and peridomiciles were found to play an important role in the dynamics of infestation. CONCLUSIONS: The contribution of this study is important for understanding the epidemiology of Chagas disease in rural areas of the state of Veracruz and will help to the establishment of an entomological surveillance system and implementation of prevention and control measures in accordance with the reality of the area.

Activity In Vitro of 2-Chloro-N-[4-(4-Chlorophenyl)-2-Thiazolyl]Acetamide Against Promastigotes of Leishmania mexicana: An Apoptosis Inducer.

PURPOSE: Leishmaniasis is an infectious disease transmitted by insects that proliferate mainly in impoverished environments of tropical climates. In the absence of an effective vaccine, pharmacological treatment is the main tool to combat this disease. The objective of this work was to analyze the anti-leishmanial activity of 2-chloro-N-[4-(4-chlorophenyl)-2-thiazolyl] acetamide (AT) in promastigotes of Leishmania mexicana. METHODS: The biological activity of the compound was evaluated using a sulphorhodamine B cytotoxicity test and the integrity of the erythrocytes was evaluated by a lysis test. The anti-trypanosomatid activity was evaluated in vitro, a cell death assay was performed by flow cytometry (IP/Annexin V stain) and a parasite growth recovery assay was performed. RESULTS: The AT showed a CC50 value of 0.031 µM for HeLa cells after 24 h of exposure, which did not induce erythrocyte lysis. On the other hand, the AT showed an IC50 value of 0.086 µM for L. mexicana (promastigote form) after 24 h of interaction. The compound was capable of inducing apoptosis in the parasites and did not allow recovery after 24 h of exposure. CONCLUSION: This study provides valuable information with the objective of developing new drugs for the treatment of this disease, although more research on this molecule is needed to improve its biological activity.

Gene expression to contaminated or not contaminated Triatoma dimidiata faeces with Trypanosoma cruzi in vivo and in vitro assay.

Triatoma dimidiata is considered one of the most important vectors in the spread of Chagas disease in Mesoamerica. Hematophagous insects may deposit faeces contaminated or not with Trypanosoma cruzi on the surface of the skin during the feeding process. In endemic areas humans can be in contact several times to this fluid before get infection. Due to limited work on the of immune response to insect's fluids in mammals. In this work, we explored the early response of chemokine and cytokines of skin tissue at the inoculation site against faeces from T. dimidiata contaminated or not with T. cruzi in murine model, also we explored the in vitro response of epitheloid cells line "HeLa cells" to this fluid. Mice were exposed intradermically to faeces free of metacyclic trypomastigotes, oneor multiple times along the experiment before challenged with faeces contaminated with metacyclic trypomastigotes, mimicking natural conditions. In in vitro assay with HeLa cells only one exposure was carried out. It was observed that mice multiexposed to faeces, induced the strong response of TNF-α and CXCL3 expression at the inoculation site; but faeces contaminated with metacyclic trypomastigotes lower the response of TNF-α, and CXCL3. In in vitro assay with HeLa cell line, the faeces induced a strong response of CXCL8 and IL-6, but the presence of faeces contaminated with metacyclic trypomastigotes lower the response of CXCL8. In contrast, to in vivo model null response of TNF α and IL-1-α was observed in HeLa cells. In conclusion, Triatoma dimidiata faeces induces at the inoculation site chemokines that mediate preferentially chemotaxis of neutrophils and macrophages but the presence of metacyclic trypomastigotes moderate their induction. Epithelial cells act as efficient sentinels producing chemokines that may recruit neutrophils and monocytes.

Trypanocidal Effect of Nano MOFs-EP on Circulating Forms of Trypanosoma cruzi.

BACKGROUND: Chagas disease caused by the parasite Trypanosoma cruzi is considered a neglected disease in several countries. One of the main problems about this disease is the lack of an effective treatment and the absence of adverse effects. T. cruzi, like most pathogenic fungi and yeasts, require specific sterols to maintain viability and proliferative capacity during their life cycle. However, the oxidation of this molecule to ergosterol peroxide has shown several biological effects, including its trypanocidal activity. METHODS: We have synthesized MOFs nanoparticles as carrier system coupled to ergosterol peroxide (MOFs-EP) and we have studied its effect on the circulating forms of the T. cruzi parasite. RESULTS: MOFs-EP possess an efficient trypanocidal activity at much lower inhibitory concentrations (ng/mL) that the concentrations shown by ergosterol peroxide (µg/mL) when administered unconjugated form. CONCLUSION: Our results open a new possibility in the biomedical application of MOFs and ergosterol peroxide in the search for new options for the treatment of Chagas disease.

Seroprevalence of Trypanosoma cruzi Infection in Pregnant Women Suggests a High Risk for Congenital Transmission in Central Veracruz, Mexico.

PURPOSE: The state of Veracruz, Mexico, is a well-recognized endemic region for Chagas disease, but congenital transmission has not been extensively studied. We estimated here the prevalence and the risk of congenital transmission of Trypanosoma cruzi in pregnant women from 27 municipalities of central Veracruz. METHODS: 528 sera from pregnant women were analyzed by ELISA and IFA assays for the detection of IgG antibodies against T. cruzi. RESULTS: The presence of anti-T. cruzi antibodies was identified in women from 17 municipalities, obtaining an overall seroprevalence of 17.0%. A higher seropositivity was observed in the municipalities of Orizaba (25.2%), Nogales (13.6%), and Río Blanco (10.5%). The results suggest that there is a high risk of congenital transmission of T. cruzi in the region. CONCLUSION: There are currently limited actions for the surveillance and control of congenital transmission of Chagas disease in Veracruz.

Design and Synthesis of IMR-23, an Oxime Derived from Nitroimidazole as an Immunomodulatory Molecule.

BACKGROUND: Adjuvants have been obtained empirically by trial and error experiments and today, there is a tendency to the rational design of adjuvants candidates, which will increasingly achieve effective and safe products. The aim of this work was to design and evaluate the compound IMR-23 derived from nitroimidazole as an immunomodulatory molecule. MATERIALS AND METHODS: The IMR-23 molecule was obtained by a condensation reaction, cytotoxicity was tested by the sulforhodamine B assay. Adjuvanticity was evaluated in vivo and in vitro in J774A.1 cells and in the mouse model, respectively. RESULTS: IMR-23 that did not show cytotoxicity on HeLa, Vero cells and macrophages J774A.1, was able to induce the production of molecules involved in the inflammatory process, such as cytokines and chemokines determined by ELISA, to induce the production of antibodies and to generate antigenspecific cells to ovalbumin and against the antigen GST-L1b. CONCLUSION: These results open the possibility of further studies to obtain a proper balance of immunogenicity- toxicity in the use of IMR-23 as an adjuvant molecule.

Insights into Ergosterol Peroxide's Trypanocidal Activity.

Trypanosoma cruzi, which causes Chagas disease, is a significant health threat in many countries and affects millions of people. Given the magnitude of this disease, a broader understanding of trypanocidal mechanisms is needed to prevent and treat infection. Natural endoperoxides, such as ergosterol peroxide, have been shown to be toxic to parasites without causing harm to human cells or tissues. Although prior studies have demonstrated the trypanocidal activity of ergosterol peroxide, the cellular and molecular mechanisms remain unknown. The results of this study indicate that a free-radical reaction occurs in T. cruzi following ergosterol peroxide exposure, leading to cell death. Using a combination of biochemical, microscopic and in silico experimental approaches, we have identified, for the first time, the cellular and molecular cytotoxic mechanism of an ergosterol peroxide obtained from Pleurotus ostreatus (Jacq) P. Kumm. f. sp. Florida.

Complexes containing benzimidazolyl-phenol ligands and Ln(III) ions: Synthesis, spectroscopic studies and preliminary cytotoxicity evaluation.

Fourteen new complexes were obtained from Ln(III)(NO3)3∙n-H2O and the chromophores 2-(1H-benzo[d]imidazol-2-yl)-phenol (Bzp1) or 2-(5-methyl-1H-benzo[d]imidazol-2-yl)-phenol (Bzp2). The complete characterization allowed us to assign unequivocally the structures of all the complexes. The techniques used for this purpose were Ultraviolet-Visible (UV-Vis) and Fourier-Transform Infrared (FT-IR) spectroscopies, High-Resolution Mass Spectrometry (HRMS), Magnetic Susceptibility (MS), Elemental Analysis (EA) and Molar Conductivity (MC). HRMS allowed us to find the molecular ion and its isotopic pattern. The FT-IR spectral data suggested that benzimidazolyl-phenol ligands coordinate with Ln(III) ions through iminic nitrogen and phenolic oxygen. Thermogravimetric Analysis (TGA) studies of NdBzp1 and GdBzp2 complexes indicate the presence of lattice water along with three nitrates and two benzimidazolyl-phenol ligands; the thermal decomposition was consistent with the minimal formula suggested by EA. The coordination type of the benzimidazolyl-phenol ligands, the geometry and the structural organization of these coordination complexes have been interpreted by Density Functional Theory (DFT) calculations, and they coincided with the physicochemical data suggesting a coordination number eight for the Ln(III) ions. The cytotoxicity of the chromophores and their coordination complexes was tested against a cancer cell line (HeLa), as compared with structure/support cells (NIH-3T3) and defense cells (J774A.1), revealing that three coordination complexes showed moderate cytotoxicity against the cell lines studied.

Prevalence of Trichomonas vaginalis and Human papillomavirus in female sex workers in Central Veracruz, Mexico.

Female sex workers (FSWs) have been considered a key population for sexually transmitted infections (STIs); therefore, they are periodically screened as a requirement to obtain a work card. However, there is insufficient epidemiological data on STIs among FSWs in Mexico. The detection of Trichomonas vaginalis is limited to microscopic studies and the molecular screening of Human papillomavirus (HPV) is only done to women 35 years of age and older. The objective of this study was to determine the prevalence of T. vaginalis and HPV infections in FSWs in the city of Orizaba, Veracruz, Mexico. Samples from 105 FSWs were obtained by cervical swab and analyzed. The identification of T. vaginalis and HPV was performed by molecular methods. HPV DNA was identified in 5.71% of the samples with the presence of HPV16, HPV18, and HPV58. A percentage of 25.7% samples were positive for T. vaginalis for optical microscopy and 23.8% for PCR. The results of the study indicate the need to incorporate more sensitive methods for the timely diagnosis of STIs as well as comprehensive health promotion programs directed to the most vulnerable groups among FSWs.

In Vitro Expression of Toll-Like Receptors and Proinflammatory Molecules Induced by Ergosta- 7,22-Dien-3-One Isolated from a Wild Mexican Strain of Ganoderma oerstedii (Agaricomycetes).

Compounds showing pharmacological activity on the immune system are of interest because of their therapeutic potential in the treatment of many diseases. However, data from primary human immune cells and in vivo studies are limited. The aim of this study was to analyze the ability to induce the expression of Toll-like receptors (TLRs) and proinflammatory molecules on cells involved in the immune system using the compound ergosta-7,22-dien-3- one, isolated from a wild Mexican strain of Ganoderma oerstedii. According to our study, ergosta-7,22-dien-3-one did not present any cytotoxic effect on HeLa or J774A.1 cells, and it was able to stimulate nitric oxide production, induce the expression of genes, and induce the production of TLRs, cytokines, chemokines, and cellular adhesion molecules in J774A.1 cells, based on reverse-transcriptase polymerase chain reaction and enzyme-linked immunosorbent assay. Here we report a new pro-inflammatory property of ergosta-7,22-dien-3-one, which should be considered as a possible adjuvant property in view of its biological activity.

Highly discordant serology against Trypanosoma cruzi in central Veracruz, Mexico: role of the antigen used for diagnostic.

BACKGROUND: Chagas disease is a parasitic disease caused by the protozoan parasite Trypanosoma cruzi. In Mexico, the burden of the disease is difficult to estimate and improving surveillance for Chagas disease is an important priority. We aimed here at determining the seroprevalence of T. cruzi infection in humans in a rural community in Veracruz. METHODS: Serum samples (196) were analyzed for T. cruzi infection using five enzyme-linked immunosorbent assay (ELISA) tests: two in-house tests based on crude parasite extract and three commercial ELISA kits. Because of highly discordant results, we further explored the importance of parasite antigens and strains by western-blot analysis. RESULTS: A total of 74 samples (37.7 %) were reactive with at least one ELISA, but discordance among tests was very high. The best agreement was between Chagatest recombinant and Chagatek ELISA (Kappa index = 0.798). The agreement between other combinations of tests ranged from 0.038 to 0.518. Discordant samples were confirmed by western-blot analysis using up to nine parasite strains, giving a seroprevalence of 33.7 %. CONCLUSIONS: Commercial tests had a very limited ability to detect T. cruzi infection in the study population. In-house tests based on crude parasite antigens showed a greater sensitivity but were still unable to detect all cases of T. cruzi infection, even when based on a local parasite strain. The high seroprevalence confirmed the hyper-endemicity of T. cruzi infection in the region. Reliable epidemiological surveillance of Chagas disease will require the development of improved diagnostic tests.

Cytotoxic activity and induction of inflammatory mediators of the methanol:chloroform extract of Fusarium moniliforme.

BACKGROUND: Fusarium moniliforme is a phytopathogenic facultative fungus with a cosmopolitan distribution in all types of climates, and has a wide host range, including, among others, bean, rice, wheat and sorghum crops. There is a current lack of knowledge regarding the potential of these fungi, so it is considered to be of great importance to obtain information related to the biological activity of extracts and secondary metabolites. AIMS: An evaluation of the role of methanol:chloroform extract of F. moniliforme in the production of inflammatory cytokines and their cytotoxic activity. METHODS: The production of nitric oxide was analyzed by the Griess method, the production of cytokines using ELISA, and the effects of the extract on cell cycle and induction of apoptosis by flow cytometry. RESULTS: The extract of F. moniliforme was seen to be able to stimulate nitric oxide (NO) production in J774A.1 cells, as well as to produce cytokines such as, IL-1ß, IL-6, and TNF-α. It was also observed that the extract of F. moniliforme produces activity on cell cycle modulation and apoptosis when tested in carcinogenic cell lines. CONCLUSIONS: The results obtained from this study open the possibility of obtaining and identifying metabolites of the extract of F. moniliforme that can be evaluated for possible use in cancer therapy.

A low density microarray method for the identification of human papillomavirus type 18 variants.

We describe a novel microarray based-method for the screening of oncogenic human papillomavirus 18 (HPV-18) molecular variants. Due to the fact that sequencing methodology may underestimate samples containing more than one variant we designed a specific and sensitive stacking DNA hybridization assay. This technology can be used to discriminate between three possible phylogenetic branches of HPV-18. Probes were attached covalently on glass slides and hybridized with single-stranded DNA targets. Prior to hybridization with the probes, the target strands were pre-annealed with the three auxiliary contiguous oligonucleotides flanking the target sequences. Screening HPV-18 positive cell lines and cervical samples were used to evaluate the performance of this HPV DNA microarray. Our results demonstrate that the HPV-18's variants hybridized specifically to probes, with no detection of unspecific signals. Specific probes successfully reveal detectable point mutations in these variants. The present DNA oligoarray system can be used as a reliable, sensitive and specific method for HPV-18 variant screening. Furthermore, this simple assay allows the use of inexpensive equipment, making it accessible in resource-poor settings.

Seroprevalence of Trypanosoma cruzi and Leishmania mexicana in free-ranging howler monkeys in southeastern Mexico.

Natural infection of wild mammals by protozoa parasites is quite common in nature. For Neotropical Primates different infections of parasites that are etiological agent of disease in human have been identified. In particular, infections by Trypanosoma cruzi and Leishmania sp., have been reported for some New World primate species, but there are no reports of infection with these parasites in any primate species in Mexico. A serological study was conducted on two howler monkey species (Alouatta pigra and A. palliata) from the Mexican states of Campeche and Tabasco. A total of 55 serum samples (20 samples from A. pigra, 20 samples from A. palliata, and 15 samples from semifree ranging A. palliata of Los Tuxtlas, Veracruz as negative controls) were analyzed for the detection of immunoglobulin G antibodies against T. cruzi and Leishmania mexicana through enzyme linked immunosorbent assay test, indirect immunofluorescence assay and Western blot. The overall prevalence of antibodies in howler monkeys was 17.5% for T. cruzi and 30% for L. mexicana. Our results also indicate that A. pigra is more susceptible to develop leishmaniasis than A. palliata. Finally, the finding of positive serology in these primates should be given serious consideration for public health, given the potential role of these primate species as wild reservoirs for these diseases and the increasing contact of monkeys with human populations due to habitat loss and fragmentation.