Rickettsia rickettsii and Rickettsia typhi in hospitalized children diagnosed with Pediatric Multisystemic Inflammatory Syndrome in Merida, Yucatan.

Multisystem Inflammatory Syndrome in Children (MIS-C) presents with fever, fatigue, elevated inflammatory markers (acute phase reactants), and a history of exposure to SARS-CoV-2 or positive antibodies to SARS-CoV-2. As the COVID-19 pandemic unfolded, the risk of MIS-C in the pediatric population increased. However, exposure to other viruses and the presence of SARS-CoV-2 positive antibodies in children hospitalized for various pathogen-associated illnesses will also remain common and may complicate differential diagnoses with diseases endemic to the region such as rickettsial diseases. The objective was to highlight the desirability of medical personnel systematically incorporating rickettsiosis as a differential diagnosis for MIS-C when studying a child with fever, non-specific symptoms, and elevated inflammatory markers. In conclusion MIS-C should be considered in children with elevated inflammatory markers when there is a history of COVID-19 and they also meet criteria that have already been established by international agencies, such as CDC and WHO.

Rickettsia rickettsii and Rickettsia typhi in hospitalized children diagnosed with Pediatric Multisystemic Inflammatory Syndrome in Merida, Yucatan

Abstract Multisystem Inflammatory Syndrome in Children (MIS-C) presents with fever, fatigue, elevated inflammatory markers (acute phase reactants), and a history of exposure to SARS-CoV-2 or positive antibodies to SARS-CoV-2. As the COVID-19 pandemic unfolded, the risk of MIS-C in the pediatric population increased. However, exposure to other viruses and the presence of SARS-CoV-2 positive antibodies in children hospitalized for various pathogen-associated illnesses will also remain common and may complicate differential diagnoses with diseases endemic to the region such as rickettsial diseases. The objective was to highlight the desirability of medical personnel systematically incorporating rickettsiosis as a differential diagnosis for MIS-C when studying a child with fever, non-specific symptoms, and elevated inflammatory markers. In conclusion MIS-C should be considered in children with elevated inflammatory markers when there is a history of COVID-19 and they also meet criteria that have already been established by international agencies, such as CDC and WHO

Clinical and laboratory features of rickettsioses in Yucatan, Mexico.

Rickettsia species are obligate intracellular bacteria that can cause mild to severe human disease. Based on phylogeny, clinical symptoms, and antigenic properties, rickettsiae are classified into four groups. Infections by these agents are characterized by clinical symptoms ranging from self-limited to severe and even fatal febrile illnesses, depending on the Rickettsia spp. involved, the patient's predisposition, and timely medical care. The present study aimed to characterize rickettsial diseases in Yucatan according to clinical and laboratory features appearing in medical records corresponding to 427 samples taken between 2015 and 2018. A study was conducted over the period 2015-2018 on 427 samples. Clinical and laboratory features were documented from the patients' medical records. For molecular diagnosis, blood was collected in 3.8 % sodium citrate as anticoagulant, and DNA was extracted. Single-step and nested PCR amplification was performed using genus-specific primers for the rickettsial 17kDa and ompB genes. The amplicons obtained were purified and sequenced. A total of 22.7 % (97/427) positive cases of Rickettsia spp. were identified by PCR from 14.15 % (15/106) of the municipalities in Yucatan. 75.2 % (73/97) of the cases were from the city of Merida during the autumn (September-December). The age groups with the highest frequency of confirmed cases were pediatric (5-14 years) (57.7 %) and adults (25-49 years) (42.2 %). There were six fatal cases in children, one associated with R. typhi and five with R. rickettsii. In non-fatal cases, 32.9 % (32/97) corresponded to the spotted fever group (SFG), and 60.8 % (59/97) to the typhus group (TG). Significant differences in signs, and laboratory data, were observed between the pediatric and adult populations. For the treatment of patients, oral and intravenous doxycycline was used in severe hospitalized cases. Typhus group and spotted fever group Rickettsiae are endemic pathological agents found in urban and rural areas of our region. Molecular identification allows for greater diagnostic accuracy and timely treatment and consequently a better prognosis. It is necessary to implement or reinforce measures focused on the dissemination of knowledge regarding rickettsial diseases and their prevention.

Perception of risk among children: Exploring the risk of TB-rickettsial disease based on the children's drawing pictures in a Mayan community of Yucatan.

Background: It is important to work on designs of health promotion strategies that involve educational interventions about the risk factors associated to TB-rickettsiosis (Tick-Borne rickettsiosis). Children's drawings provide a window into their thoughts and feelings. The aim was to analyze children's risk perceptions regarding by the presence of ticks in a rural community in southeast Mexico. Methods: The main framework used was a social cognitive perspective under the Health Belief Model. Study was carried out in rural elementary schools and included a drawing contest. A total of 224 children (8-12 years old) participated. Drawings were coded and classified; descriptive trend analysis was performed using counts and percentages. The qualitative data was analyzed by researcher experts in TB- rickettsiosis and using Atlas ti V.8. Results: Results are presented in seven categories that consider environmental elements, actors, and cognitive aspects. The environmental context, 99.1% of the drawings represent sites outside the home (92% include vegetation with the presence of ticks in their immediate external environment). In the actors' category, 69.6% included people carrying out activities (prevention and risk). As for the cognitive aspects, 70% included domestic pets and 13.4% farmyards animals. Conclusion: The children expressed their ideas about risk factors and preventive measures against TB-rickettsiosis with a self-care approach. They acquired knowledge about preventive strategies and clinical symptoms. It is necessary to evaluate what happens after an intervention and how they implement in their lives what they have learned.

Tick-associated diseases identified from hunting dogs during the COVID-19 pandemic in a Mayan community in Yucatan, Mexico.

Background: Hunting activity in the Mayan communities has increased due to COVID-19 and domestic dogs have gained more importance. Due to their proximity to humans, domestic dogs are a bridge between tick-borne diseases (TBDs) and humans and their peri-domestic environment. In Mexico, and especially in rural regions, there were not adequate records of TBDs during the SARS-CoV-2 pandemic. Aim: Identify TBD of ticks collected during the COVID-19 pandemic in a rural community. Methods: Tick capture was carried out in March 2021, in Teabo, Yucatan. Ticks were removed using from domestic dogs and placed in ethanol. Collected ticks were morphologically identified and underwent DNA extraction and a partial segment of the mitochondrial 16S-rDNA gene was amplified to corroborate the tick species. The DNA was screened for the presence of Anaplasma spp., Borrelia spp., Ehrlichia spp., and Rickettsia spp. Purified amplification products were submitted for sequencing and the results were compared to those deposited in GenBank using BLAST. Results: We collected 33 ectoparasites, Ixodes affinis, Rhipicephalus sanguineus, Rhipicephalus microplus, and Amblyomma mixtum on 11 hunting dogs. The most frequent ectoparasite was R. sanguineus (66%). We detected the presence of DNA of Rickettsia endosymbiont in I. affinis and Anaplasma platys in R. sanguineus. Rickettsia endosymbiont presented a similarity of 100% with the partial sequence of R. endosymbiont of I. affinis isolate IACACTM001 16S ribosomal RNA gene and the sequence of A. platys had a similarity of 100% with the partial sequence of the isolate 23-33TX 16S ribosomal RNA gene of A. platys from dogs from Texas, USA and with the partial sequence of the isolate L134 16S ribosomal RNA gene of Ehrlichia canis from dogs from Piura, Peru. Conclusion: We confirmed for the first time the presence of A. platys in R. sanguineus and R. endosymbiont in I. affinis ticks from dogs in the state of Yucatan.

Rickettsia Vaccine Candidate pVAX1-OmpB24 Stimulates TCD4+INF-γ+ and TCD8+INF-γ+ Lymphocytes in Autologous Co-Culture of Human Cells.

BACKGROUND: In recent years, promising vaccination strategies against rickettsiosis have been described in experimental animal models and human cells. OmpB is considered an immunodominant antigen that is recognized by T and B cells. The aim of this study was to identify TCD4+INF-γ+ and TCD8+INF-γ+ lymphocytes in an autologous system with macrophages transfected with the vaccine candidate pVAX1-OmpB24. Lymphocytes and monocytes from 14 patients with Rickettsia were isolated from whole blood. Monocytes were differentiated into macrophages and transfected with the plasmid pVAX1-OmpB24 pVax1. Isolated lymphocytes were cultured with transfected macrophages. IFN-γ-producing TCD4+ and TCD8+ lymphocyte subpopulations were identified by flow cytometry, as was the percentage of macrophages expressing CD40+, CD80+, HLA-I and HLA-II. Also, we analyzed the exhausted condition of the T lymphocyte subpopulation by PD1 expression. Macrophages transfected with pVAX1-OmpB24 stimulated TCD4+INF-γ+ cells in healthy subjects and patients infected with R. typhi. Macrophages stimulated TCD8+INF-γ+ cells in healthy subjects and patients infected with R. rickettsii and R. felis. Cells from healthy donors stimulated with OmpB-24 showed a higher percentage of TCD4+PD1+. Cells from patients infected with R. rickettsii had a higher percentage of TCD8+PD-1+, and for those infected with R. typhi the larger number of cells corresponded to TCD4+PD1+. Human macrophages transfected with pVAX1-OmpB24 activated TCD4+IFN-γ+ and CD8+IFN-γ+ in patients infected with different Rickettsia species. However, PD1 expression played an important role in the inhibition of T lymphocytes with R. felis.

First exploratory study of bacterial pathogens and endosymbionts in head lice from a Mayan community in southern Mexico.

Lice represent one of the most neglected group of vectors worldwide, particularly in Latin America. Records of bacterial agents related to head lice are non-existent in this region of the continent. Many of these communities often do not have adequate access to public services and/or health protection. The normalization of this condition prevents them from manifesting discomfort, such as bites and itching, which further aggravates the situation, as they can be vectors of important diseases. For this reason, the aim of this work was to identify the richness of bacterial pathogens (Acinetobacter, Bartonella, and Rickettsia) and endosymbionts (Wolbachia) in head lice of paediatric patients from the indigenous municipality of Hoctun, Yucatan, Mexico. DNA extraction was performed using the QIAamp DNA Mini Kit. For the detection of bacterial pathogens, fragments of the gltA, rpoB, and 16S rDNA genes were amplified. For the detection of Wolbachia, the wsp gene was amplified. Of the 28 lice analysed, the presence of two genera of bacterial pathogens was detected Acinetobacter (42.9% = 12/28) and Bartonella (7.14% = 2/28). We also detected the endosymbiont Wolbachia (71.42% = 20/28). Our results showed that DNA from three bacteria species (Acinetobacter baumannii, Bartonella quintana, and Wolbachia pipientis) was present with frequencies ranging from 3.57% to 71.42%. This work represents the first exploratory study of the diversity of agents associated with head lice (Pediculus humanus capitis) in Mexico and Latin America. Due to the findings generated in the present study, it is important to perform surveillance of head lice populations to identify the degree of spread of these pathogens and their impact on populations in the region.

Understanding risk perception from traditional knowledge of Mayan farmers on Rickettsioses.

Rickettsioses are a group of tick-borne infectious diseases. The clinical presentation is characterised by unspecified manifestations seen in illnesses such as dengue, zika, and chikungunya, so identification is complicated. The greatest impact occurs among the world's poorest populations. Rickettsioses have hardly been studied from a qualitative perspective to show the cultural horizon of the people affected. We aimed to describe the perception of Mayan indigenous farmers about their risk perception for disease transmission. We used the ethnographic method and built life stories. From the perspective of people interviewed, their relationship with the reservoirs for vectors did not represent a high risk, did not consider that blisters and other skin lesions are caused by tick bites. Contributions as this article show the thinking logic underlying the perception of risk of these impoverished populations. To produce synergy with prevention efforts, it is necessary to know the cultural perspectives of targeted groups.

Personal and household factors involved in recent Rickettsia exposure in a rural population from Yucatán, Mexico.

The aim of the study was to describe the epidemiological factors associated with the risks of recent Rickettsia exposure in inhabitants of a rural population from Yucatán, Mexico. The study included 130 inhabitants from Maxcanú, Yucatán. Blood samples were collected to detect IgM and IgG antibodies against Rickettsia typhi and Rickettsia rickettsii by an indirect immunofluorescence antibody test. Additionally, nested polymerase chain reaction was performed to amplify fragments of the 17kDa and sca5 genes. Previously, an epidemiological questionnaire was applied focused on collecting information on personal and housing exposure variables related to the recent infection with Rickettsia to determine epidemiological associations. Results that exhibited a p-value < .25 were included in a generalized multinomial logistic linear model to determine the variables involved with the risk of contact or Rickettsia infection. In all, 76% (99/130) of the participants presented with immunoglobulin titres against the Rickettsia species evaluated, while rickettsial DNA was detected in 35.4% (46/130) of the participants. The association analysis with the personal exposure variables showed that the productive age group (OR = 0.32; 95% CI = 0.10-1.03) and the elders group (OR = 0.12; 95% CI = 0.01-0.83) were protective factors for recent infection with R. typhi, taking as reference the school group. The presence of a family orchard in the home (OR = 7.56; 95% CI = 1.62-35.29) was a risk factor for recent infection with R. rickettsii. Presumably, the presence of ectoparasites (OR = 2.71; 95% CI = 0.90-8.09) at home was a risk factor for recent infection with both Rickettsia species. Recent infection was demonstrated in inhabitants from Maxcanú, Yucatán. A high seropositive frequency was obtained. The results highlight the importance of the family garden and the presence of ectoparasites in the home as risk factors associated with recent infection with Rickettsia in inhabitants from Maxcanú.

TTV, what is it and what do we know in Mexico? / TTV, ¿qué es y qué sabemos en México?

The aim of this editorial is to present a brief description of the Torque teno virus' epidemiology and establish the actuality of their study in México. Also, we mentioned the studies made in México and Yucatán, specifically in the Center of Regional Research "Dr. Hideyo Noguchi" of the Autonomous University of Yucatán.

El objetivo de esta editorial es presentar una breve descripción de la epidemiología del Torque teno virus, así como establecer la actualidad del escenario de su estudio en México. Además, hacemos mención de los estudios hechos en México y en Yucatán, específicamente en el Centro de Investigaciones Regionales "Dr. Hideyo Noguchi", de la Universidad Autónoma de Yucatán.

Detection of hand, foot and mouth disease in the yucatan peninsula of Mexico.

We report a case of hand, foot and mouth disease (HFMD) in a 5-year-old male from Merida City in the Yucatan Peninsula of Mexico. A clinical and physical examination revealed that the patient had symptoms typical of HFMD, including fever, fatigue, odynophagia, throat edema, hyperemia, lesions on the hands and feet, and blisters in the oral cavity. The patient fully recovered after a convalescence period of almost three weeks. Reverse transcription-polymerase chain reaction and nucleotide sequencing revealed that the etiological agent was enterovirus 71 (EV71). The sequence has greatest (90.4%) nucleotide identity to the corresponding regions of EV71 isolates from the Netherlands and Singapore. Although HFMD is presumably common in Mexico, surprisingly there are no data in the PubMed database to support this. This case report provides the first peer-reviewed evidence of HFMD in Mexico.

Serologic evidence of flavivirus infection in bats in the Yucatan Peninsula of Mexico.

We captured 140 bats of seven species in Merida City in the Yucatan Peninsula of Mexico in 2010. Serum was collected from each bat and assayed by plaque reduction neutralization test (PRNT) using six flaviviruses: West Nile virus, St. Louis encephalitis virus, and dengue viruses 1-4. Flavivirus-specific antibodies were detected in 26 bats (19%). The antibody-positive bats belonged to three species: the Pallas's long-tongued bat (Glossophaga soricina), Jamaican fruit bat (Artibeus jamaicensis), and great fruit-eating bat (Artibeus lituratus), and their flavivirus antibody prevalences were 33%, 24%, and 9%, respectively. The PRNT titers were usually highest for dengue virus 2 or dengue virus 4, but none of the titers exceeded 80. These data could indicate that most of the antibody-positive bats had been infected with dengue virus. However, because all titers were low, it is possible that the bats had been infected with another (perhaps unrecognized) flavivirus not included in the PRNT analysis, possibly a virus more closely related to dengue virus than to other flaviviruses. Each serum sample was assayed for flavivirus RNA by reverse transcription PCR, but all were negative.

Antibodies to West Nile virus in asymptomatic mammals, birds, and reptiles in the Yucatan Peninsula of Mexico.

Surveillance for evidence of West Nile virus (WNV) infection in taxonomically diverse vertebrates was conducted in the Yucatan Peninsula of Mexico in 2003 and 2004. Sera from 144 horses on Cozumel Island, Quintana Roo State, 415 vertebrates (257 birds, 52 mammals, and 106 reptiles) belonging to 61 species from the Merida Zoo, Yucatan State, and 7 farmed crocodiles in Ciudad del Carmen, Campeche State were assayed for antibodies to flaviviruses. Ninety (62%) horses on Cozumel Island had epitope-blocking enzyme-linked immunosorbent assay (ELISA) antibodies to flaviviruses, of which 75 (52%) were seropositive for WNV by plaque reduction neutralization test (PRNT). Blocking ELISA antibodies to flaviviruses also were detected in 13 (3%) animals in the Merida Zoo, including 7 birds and 2 mammals (a jaguar and coyote) seropositive for WNV by PRNT. Six (86%) crocodiles in Campeche State had PRNT-confirmed WNV infections. All animals were healthy at the time of serum collections and none had a history of WNV-like illness.

Picobirnavirus: nuevo agente viral como probable causante de la diarrea infecciosa aguda en lechones lactantes de granjas porcícolas del estado de Yucatán, México / picobirnaviruses: new viral agent as cause of acute infection disease in pig farms in the state of Yucatan, Mexico

En 1988, en Brasil, Pereira describió un nuevo grupo de virus con genoma bisegmentado de ácido ribonucleico (ARN), al que nombró picobirnavirus (PBV), desde entonces éste se ha localizado en animales y en humanos de todo el mundo. En México no existe ningún dato sobre este virus, por lo que al encontrar patrones electroforéticos semejantes a los mencionados en tres muestras de heces de lechones con diarrea infecciosa aguda(DIA), se decidió identificar este hallazgo de dos segementos de ARN encontrando por medio de la técnica de electroforesis en geles de poliacrilamida (PAGE) con tinción de nitrato de plata. De las muestras analizadas, 74 presentaron un patrón electroforético de 11 segmentos de ARN característico de los rotavirus (RV) y en 3 muestras se observaron únicamente 2 bandas con distribución diferente a los RV. A estas 3 muestras se les realizó digestión enzimática con DNAsa I y RNAsa A, encontrándose que corresponden a segmentos de ARN de doble cadena de aproximadamente 2600-1600 pares de bases, semejante a lo que se ha informado para los "picobirnavirus"; por lo que estos hallazgos sugieren la existencia de un virus con dos segmentos de doble cadena de ARN, que son partículas representativas de un nuevo virus intestinal, asociado con gastroenteritis en lechones, aunque no se conoce el papel que desempeña en ellas

Antucuerpos contra el virus de inmunodeficiencia humana en una población homosexual population / Antibodies against human immunodeficiency virus in a homosexual population

Entre agosto de 1987 y febrero de 1988, se reclutaron en forma voluntaria a través de la comunidad homosexual de Cancún, quintana Roo, 60 homosexuales masculinos en quienes se realizó un estudio seroepidemiológico transversal en relación con anticuerpos contra el Virus de Inmunodeficiencia Humana. Se detectó seropositividad (a través de ensayo inmunoenzimático y electroinmuno transferencia) en seis sujetos estudiados. No se encontró relación estadísticamente significativa entre la seropositividad y la edad, nivel socieconómico y el atecedente de relaciones sexuales con extranjeros. Se pudo establecer una relación estadísticamente significativa entre la seropsitividad y el número de relaciones sexuales/mes y el número de parejas sexuales/mes. Las prácticas bisexuales fueron un hecho frecuente en todo el grupo. Dos sujetos seropositivos se clasificaron en la etapa II de la infección del VIH, uno en etapa III, dos en etapa IV-A y uno más en etapa IV-c2

Between augustl1987, and february/1988, 60 homosexual-men from Cancun, Q. Roo, Mexico, were studied determine the prevalence of my antibodies (Elisa and Western Blot). Six subjects were seropositive. No relationship was found between HIV antibodies and age, socioeconomic level or sexual intercourse with foreing subjects. The number of sexual partners/month, and the number of sexual intercourses/month were associate with the presence of HIV antibodies. Bisexual practice were found in 43 percent of all the group. Two subjec with my antibodies were classified in the phase II of HIV infection, one in phase III, two in phase IV-A and one more in phase IV-c2.