Molecular detection of hemotropic Mycoplasma and Bartonella species in lice from sheep and goats of Mexico

The knowledge of lice associated with small ruminants, especially sheep and goats, is scarce. In Mexico, there are historical reports of six species of chewing and sucking lice associated with Capra hircus and Ovis canadensis. However, the reports did not analyze the ecology of the infestations or the presence of potentially pathogenic bacteria. For this reason, the objectives of this study were i) to identify the species of lice associated with sheep and goats in three states of the Mexican Republic, ii) to characterize the infestations, and iii) to identify the presence of bacterial pathogens. From October 2019 to August 2021, six ranches with sheep and goats were sampled in the states of Hidalgo and Veracruz. Hosts were visually inspected, and lice were retrieved with forceps. The specimens were sexed and identified using morphological taxonomic keys. DNA extraction was performed individually, and a fragment of the cytochrome oxidase subunit 1 gene (COI) was amplified for the molecular identification of the specimens. Subsequently, Anaplasma, Bartonella, Ehrlichia, Mycoplasma, and Rickettsia were molecularly detected. Additionally, the infestations were characterized by calculating the prevalence and mean abundances. We collected 563 specimens of three species, Bovicola caprae, Bovicola ovis, and Linognathus africanus. The highest infestation levels were recorded for B. ovis (66.7%; 4.4) from Veracruz. Additionally, two Bartonella species were detected: Bartonella mellophagi in B. ovis and Bartonella capreoli in L. africanus. In contrast, Mycoplasma ovis was detected exclusively in one pool of B. ovis. This study provides new bacterial-ectoparasite associations and highlights the possible role of these neglected ectoparasites as vectors in the populations of sheep and goats from Mexico.

The Low Variability of Tc24 in Trypanosoma cruzi TcI as an Advantage for Chagas Disease Prophylaxis and Diagnosis in Mexico

(1) Background: Chagas disease is the main neglected tropical disease in America. It is estimated that around 6 million people are currently infected with the parasite in Latin America, and 25 million live in endemic areas with active transmission. The disease causes an estimated economic loss of USD 24 billion dollars annually, with a loss of 75,200 working years per year of life; it is responsible for around ~12,000 deaths annually. Although Mexico is an endemic country that recorded 10,186 new cases of Chagas disease during the period of 1990–2017, few studies have evaluated the genetic diversity of genes that could be involved in the prophylaxis and/or diagnosis of the parasite. One of the possible candidates proposed as a vaccine target is the 24 kDa trypomastigote excretory–secretory protein, Tc24, whose protection is linked to the stimulation of T. cruzi-specific CD8+ immune responses. (2) Methods: The aim of the present study was to evaluate the fine-scale genetic diversity and structure of Tc24 in T. cruzi isolates from Mexico, and to compare them with other populations reported in the Americas with the aim to reconsider the potential role of Tc24 as a key candidate for the prophylaxis and improvement of the diagnosis of Chagas disease in Mexico. (3) Results: Of the 25 Mexican isolates analysed, 48% (12) were recovered from humans and 24% (6) recovered from Triatoma barberi and Triatoma dimidiata. Phylogenetic inferences revealed a polytomy in the T. cruzi clade with two defined subgroups, one formed by all sequences of the DTU I and the other formed by DTU II–VI; both subgroups had high branch support. Genetic population analysis detected a single (monomorphic) haplotype of TcI throughout the entire distribution across both Mexico and South America. This information was supported by Nei’s pairwise distances, where the sequences of TcI showed no genetic differences. (4) Conclusions: Given that both previous studies and the findings of the present work confirmed that TcI is the only genotype detected from human isolates obtained from various states of Mexico, and that there is no significant genetic variability in any of them, it is possible to propose the development of in silico strategies for the production of antigens that optimise the diagnosis of Chagas disease, such as quantitative ELISA methods that use this region of Tc24.

Seroprevalence of Trypanosoma cruzi in Eight Blood Banks in Mexico

BACKGROUND

The true prevalence of Chagas disease in Mexico is unknown. However, it has been estimated that 1.1-4 million people are infected with Trypanosoma cruzi, which represents a potential risk for transmission of the disease via contaminated blood.

AIM OF THE STUDY

To determine the Chagas disease seroprevalence in donors from eight blood banks in the north of Mexico City, and the northeast of the State of Mexico.

STUDY DESIGN AND METHODS

Serum samples from blood donors (n = 515,038) were tested to detect the presence of anti-Trypanosoma cruzi antibodies in eight blood banks. The serologic screening test was performed in each of the blood banks. To confirm the seropositive blood donors, only two out of the eight blood banks used a test with a different principle with the aim of identifying anti-Trypanosoma cruzi antibodies. All tests were validated by the Mexican Institute for Epidemiological Diagnosis and Reference.

RESULTS

One thousand two hundred and ten blood donors were seropositive for Trypanosoma cruzi, which represents a 0.23% seroprevalence (95% CI 0.22-0.25%). Of the seropositive blood donors, 97.03 % resided in the northeast area of the State of Mexico, Mexico City, and southern part of the State of Hidalgo.

CONCLUSIONS

Active transmission of Chagas disease may be occurring in non-endemic regions in the northeast of the State of Mexico.

Seroprevalence and geographical distribution of sero-positive blood donors to Trypanosoma cruzi at the central blood bank of the National Medical Center "La Raza"

BACKGROUND

Trypanosoma cruzi is a protozoan parasite that causes Chagas disease endemic to Latin-America. It is estimated that 1.0 to 1.5% of Mexicans are infected with T. cruzi, which constitutes a potential risk of disease transmission via contaminated blood. New cases are being reported worldwide due to the migration of infected people from endemic areas.

STUDY DESIGN AND METHODS

Serum samples were collected from donors at the Central Blood Bank of the National Medical Center "La Raza" from July 2008 to December 2015 and analyzed for T. cruzi antibodies using Enzyme-linked Immunosorbent Assays. Blood donors were classified serologically as either negative or positive for Chagas disease based on the Official Mexican Standard NOM-032-SSA2-2014. The geographical distribution of sero-positive donors for Chagas disease was then determined based on the donor's areas of residence.

RESULTS

Of the 510, 047 donors, 595 tested positive for Chagas disease. We found a prevalence of 0.12%, was higher in males (0.13%) than females (0.08%) In both genders, there were more sero-positive donors aged 51-65 years as compared to other age groups. Overall there were more positive donors from the State of Mexico, northern area of Mexico City, and southern area of Hidalgo State, with rates of 67.4%, 20.6%, and 5.9%, respectively.

CONCLUSIONS

The seroprevalence of Chagas disease in blood donors attending to La Raza BB is low. Chagas disease is more prevalent in the older age groups; most sero-positive donors are from areas considered non-endemic to Chagas disease.