Biology subjects

Neves, L.

Publications and source records attributed to Neves, L..

4 recordsLinked to original sources

bioRxiv2026

Toward closing a heartwater monitoring gap with a new pan-species ELISA suitable for domestic ruminants, wildlife, and camels.

Heartwater, caused by the tick-borne bacterium Ehrlichia ruminantium, threatens ruminant production in sub-Saharan Africa and the Caribbean. Serological surveillance relies on species-specific ELISAs, so wildlife and camelids, which are potential reservoirs or sentinels, have no validated tools. We developed and evaluated a pan-species indirect ELISA prototype (ID Screen Ehrlichia ruminantium Indirect Multi-species, Innovative Diagnostics) that detects anti-MAP1-B antibodies in all mammals. A positivity threshold of 30% relative positivity percentage (RPP) was empirically established from 707 heartwater-negative cattle, goat and sheep sera from three regions (maximum RPP 22.1%). Against a goat-specific reference ELISA (n = 503), the prototype showed 98.2% sensitivity, 97.2% specificity and 97.6% overall agreement. ROC analysis identified a Youden-optimal cut-off of 29.96%, confirming the empirical threshold. Inter-assay reproducibility was satisfactory (mean CV 7.4%), and qualitative classification remained stable across runs, including for a near-threshold sample. In four vaccinated sheep, the prototype detected seroconversion at the same time points as a sheep-specific ELISA. In non-domestic hosts, the assay gave uniformly low RPP values in 24 zoo animals of ten species from a heartwater-free area. By contrast, 4.5% of 111 dromedary camels from Chad exceeded the threshold. Eight wildlife species from Kruger National Park (n = 405) were tested and five species presented high median RPP values. This single-protocol assay provides a reproducible tool for integrated heartwater surveillance across livestock, camelids and wildlife, in Africa, in the Caribbean and in all countries threatened by the emergence of heartwater.

microbiology↗

bioRxiv2025

Evaluation of the vectorial competence of Glossina brevipalpis in the transmission of Trypanosoma congolense-savannah type, in the Matutuine District, Maputo Province, Mozambique

African Animal Trypanosomosis (AAT) is a parasitic disease caused by trypanosome species, posing a major challenge to animal health and production in Africa. In the Matutuine District, southern Mozambique, where Glossina brevipalpis is prevalent, AAT is endemic. Previous research conducted in South Africa suggested that G. brevipalpis plays a marginal role in the transmission of Trypanosoma congolense. However, considering the wide distribution of G. brevipalpis in Southeast Africa and the major epidemiological implications of the aforementioned observations, this study was designed to re-assess the vectorial competence of G. brevipalpis in the transmission of T. congolense-savannah type. The research involved 915 G. brevipalpis flies, fed six times on two cattle infected with T. congolense. After 48 hours, the flies were later fed on a non-infected animal to clean the proboscis, followed by extended feeding on four susceptible cattle for 22 days. These five clean animals were monitored for 60 days based on body temperature, packed cell volume, buffy coat technique and polymerase chain reaction. In the meantime, flies were dissected weekly to observe the development of trypanosomes in the midgut and proboscis. To discard any possible mechanical transmission by G. brevipalpis 48 hours after an infected blood meal, 97 flies from a colony were fed once on two infected cattle and once on a susceptible bovine. The Spearman correlation and Mann-Whitney U tests were used to analyse the data. Results showed that the four susceptible cattle became infected with T. congolense, while the animal used for proboscis cleaning and discard any mechanical transmission remained uninfected. Dissections revealed that 89% of flies were positive for trypanosome through microscopy and 100% through PCR. These findings confirm that G. brevipalpis is a competent biological vector for transmitting T. congolense, challenging earlier assumptions and emphasizing its role in AAT dynamics.

ecology↗

bioRxiv2025

Unravelling genetic differentiation between Glossina brevipalpis populations from two distant National Parks in Mozambique

African trypanosomosis (AT), caused by protozoan parasites of the genus Trypanosoma, has plagued the African continent for centuries, affecting both humans and animals. Vector control represents an efficient way to reduce the burden of AT. In Mozambique, control campaigns reshaped tsetse fly distribution to what it is today, with Glossina brevipalpis and G. austeni as the dominant species in the South. Additionally, G. brevipalpis can be found in two National parks, Gorongosa National Park in the Centre and Maputo National Park in the South, with an 840 km wide tsetse-free zone between them. In order to improve our knowledge of the genetic diversity and gene flow of these populations and their probable isolation, we undertook a population genetics study with 11 microsatellite loci. We found that these two zones behave as isolated subpopulations, only exchanging a few individuals per year. To explain this finding, we suggest the existence of undocumented pocket populations between the two parks, or, in the absence of these, the accidental translocation of tsetse flies during human-driven animal transportation. We concluded that such undocumented means of dispersal should be explored further in studies investigating Glossina populations, to allow for the design of more efficient control strategies.

evolutionary biology↗

bioRxiv2021

Associations Between Vocal Emotion Recognition and Socio-emotional Adjustment in Children

The human voice is a primary channel for emotional communication. It is often presumed that being able to recognise vocal emotions is important for everyday socio-emotional functioning, but direct empirical evidence for this remains scarce. Here, we examined relationships between vocal emotion recognition and socio-emotional adjustment in children. The sample included 6 to 8-year-old children (N = 141). The emotion tasks required them to categorise five emotions conveyed by nonverbal vocalisations (e.g., laughter, crying) and speech prosody: anger, disgust, fear, happiness, sadness, plus neutrality. Socio-emotional adjustment was independently evaluated by the childrens teachers using a multi-dimensional questionnaire of self-regulation and social behaviour. Based on frequentist and Bayesian analyses, we found that higher emotion recognition in speech prosody related to better general socio-emotional adjustment. This association remained significant even after accounting for the childrens general cognitive ability, age, sex, and parental education in multiple regressions. Follow-up analyses indicated that the advantages were particularly robust for the socio-emotional dimensions prosocial behaviour and cognitive and behavioural self-regulation. For emotion recognition in nonverbal vocalisations, no associations with socio-emotional adjustment were found. Overall, these results support the close link between childrens emotional prosody recognition skills and their everyday social behaviour.

neuroscience↗