Heavy metals and trace elements in maternal blood and prevalence of congenital limb abnormalities among newborns: the Japan Environment and Children's Study.

BACKGROUND: Heavy metals such as lead (Pb) and cadmium (Cd) have been associated with adverse pregnancy and developmental outcomes, including congenital abnormalities. This study investigated the association between exposure to heavy metals and trace elements during fetal life and congenital limb abnormalities in infants. METHODS: This study is based on a prospective ongoing nationwide birth cohort from the Japan Environment and Children's Study (JECS). The concentrations of Cd, Pb, mercury (Hg), selenium (Se), and manganese (Mn) were measured in maternal blood collected during the mid-late trimesters. Inclusion criteria were available from questionnaires filled in during pregnancy, including information about congenital limb abnormalities at birth or at one month. To examine the associations with limb anomalies and individual chemicals, logistic regression models were applied following log-transformation or division into quartiles of Cd, Pb, Hg, Se, and Mn concentrations. To assess the associations with the heavy metals and trace elements mixture, quantile g-computation was employed. All models were adjusted for age, maternal smoking history, maternal alcohol intake, history of smoking, and infant sex. RESULTS: Data from 90,163 participants were included in the analysis, of whom 369 had congenital limb abnormalities in any of the collected information, and 89,794 had none. Among the 369 cases of congenital limb abnormalities, there were 185 and 142 cases of polydactyly and syndactyly, respectively. The median concentrations of Pb, Cd, Hg, Se, and Mn were 5.85, 0.66, 3.64, 168, and 15.3 ng/g, respectively. There were no associations between maternal blood concentrations of Pb [adjusted odd ratio = 0.83; 95% confidence interval = 0.61, 1.11], Cd [0.87; 0.68, 1.10], Hg [0.88; 0.73, 1.07], Se [1.07; 0.44, 2.59], and Mn [0.91; 0.64, 1.30] with congenital limb abnormalities. No significant association was observed between the mixture of heavy metals and trace elements [0.85; 0.72, 1.02] and any congenital limb abnormalities. Moreover, there was no association with all polydactylies and all syndactylies, or any type of abnormality as a subdivision. CONCLUSION: At the maternal exposure levels of Cd, Pb, Hg, Se, and Mn assessed in the present study, no association was identified with the risk of developing congenital limb abnormalities in children.

Molecular identification of trypanosomes in cattle in Malawi using PCR methods and nanopore sequencing: epidemiological implications for the control of human and animal trypanosomiases.

This study aimed to identify trypanosomes infecting cattle in Malawi in order to understand the importance of cattle in the transmission dynamics of Human African Trypanosomiasis (HAT) and Animal African Trypanosomosis (AAT). A total of 446 DNA samples from cattle blood from three regions of Malawi were screened for African trypanosomes by ITS1 PCR. The obtained amplicons were sequenced using a portable next-generation sequencer, MinION, for validation. Comparison of the results from ITS1 PCR and MinION sequencing showed that combining the two methods provided more accurate species identification than ITS1 PCR alone. Further PCR screening targeting the serum resistance-associated (SRA) gene was conducted to detect Trypanosoma brucei rhodesiense. Trypanosoma congolense was the most prevalent Trypanosoma sp., which was found in Nkhotakota (10.8%; 20 of 185), followed by Kasungu (2.5%; 5 of 199). Of note, the prevalence of T. b. rhodesiense detected by SRA PCR was high in Kasungu and Nkhotakota showing 9.5% (19 of 199) and 2.7% (5 of 185), respectively. We report the presence of animal African trypanosomes and T. b. rhodesiense from cattle at the human-livestock-wildlife interface for the first time in Malawi. Our results confirmed that animal trypanosomes are important causes of anemia in cattle and that cattle are potential reservoirs for human African trypanosomiasis in Malawi.

TITLE: Identification moléculaire des trypanosomes chez les bovins du Malawi, à l'aide de méthodes de PCR et du séquençage par nanopores : implication épidémiologique pour le contrôle des trypanosomiases humaines et animales. ABSTRACT: Cette étude visait à identifier les trypanosomes infectant les bovins au Malawi afin de comprendre l'importance des bovins dans la dynamique de transmission de la trypanosomiase humaine africaine (THA) et de la trypanosomose animale africaine (TAA). Au total, 446 échantillons d'ADN de sang de bovins provenant de trois régions du Malawi ont été soumis à un dépistage des trypanosomes africains par PCR de l'ITS1. Les amplicons obtenus ont été séquencés à l'aide d'un séquenceur portable de nouvelle génération, MinION, pour validation. La comparaison des résultats de la PCR de l'ITS1 et de la séquence MinION a montré que la combinaison des deux méthodes permettait une identification plus précise des espèces que la seule PCR de l'ITS1. Un autre dépistage par PCR ciblant le gène SRA (associé à la résistance du sérum) a été effectué pour détecter Trypanosoma brucei rhodesiense. Trypanosoma congolense était l'espèce de trypanosome la plus répandue, trouvée à Nkhotakota (10,8 % ; 20 sur 185), suivi de Kasungu (2,5 % ; 5 sur 199). Notamment, la prévalence de T. b. rhodesiense détectée par PCR de SRA était élevée à Kasungu et Nkhotakota, avec respectivement 9,5 % (19 sur 199) et 2,7 % (5 sur 185). Nous rapportons la présence de trypanosomes animaux africains et de T. b. rhodesiense de bovins à l'interface homme-bétail-faune sauvage, pour la première fois au Malawi. Nos résultats confirment que les trypanosomes animaux sont des causes importantes d'anémie chez les bovins et que les bovins sont des réservoirs potentiels pour la trypanosomiase humaine africaine au Malawi.

A single test approach for accurate and sensitive detection and taxonomic characterization of Trypanosomes by comprehensive analysis of internal transcribed spacer 1 amplicons.

To improve our knowledge on the epidemiological status of African trypanosomiasis, better tools are required to monitor Trypanosome genotypes circulating in both mammalian hosts and tsetse fly vectors. This is important in determining the diversity of Trypanosomes and understanding how environmental factors and control efforts affect Trypanosome evolution. We present a single test approach for molecular detection of different Trypanosome species and subspecies using newly designed primers to amplify the Internal Transcribed Spacer 1 region of ribosomal RNA genes, coupled to Illumina sequencing of the amplicons. The protocol is based on Illumina's widely used 16s bacterial metagenomic analysis procedure that makes use of multiplex PCR and dual indexing. Results from analysis of wild tsetse flies collected from Zambia and Zimbabwe show that conventional methods for Trypanosome species detection based on band size comparisons on gels is not always able to accurately distinguish between T. vivax and T. godfreyi. Additionally, this approach shows increased sensitivity in the detection of Trypanosomes at species level with the exception of the Trypanozoon subgenus. We identified subspecies of T. congolense, T. simiae, T. vivax, and T. godfreyi without the need for additional tests. Results show T. congolense Kilifi subspecies is more closely related to T. simiae than to other T. congolense subspecies. This agrees with previous studies using satellite DNA and 18s RNA analysis. While current classification does not list any subspecies for T. godfreyi, we observed two distinct clusters for these species. Interestingly, sequences matching T. congolense Tsavo (now classified as T. simiae Tsavo) clusters distinctly from other T. simiae Tsavo sequences suggesting the Nannomonas group is more divergent than currently thought thus the need for better classification criteria. This method presents a simple but comprehensive way of identification of Trypanosome species and subspecies-specific using one PCR assay for molecular epidemiology of trypanosomes.