Search bioRxiv⌕ Search

Biology subjects

de Oliveira, R. C.

Publications and source records attributed to de Oliveira, R. C..

2 recordsLinked to original sources

Lessons from a multilaboratorial task force for diagnosis of a fatal toxoplasmosis outbreak in captive primates in Brazil

As exemplified by the Coronavirus Disease 2019 (COVID-19) pandemic, infectious diseases may emerge and spread rapidly, often causing serious economic losses and public health concerns. In fact, disease outbreaks have become increasingly common, especially those of zoonotic origin. The Brazilian Ministry of Health is responsible for national epizootic surveillance. However, the systems focus primarily on diseases affecting humans has led to the neglect of other zoonotic diseases. In this report, we present an integrated investigation of an outbreak that occurred during the first year of the COVID-19 pandemic among captive neotropical primates housed at a primatology center in Brazil. After presenting a range of non-specific clinical signs, including fever, prostration, inappetence, and abdominal pain, ten primates from five different species died within approximately four days. Despite the state of health emergency due to the pandemic, a network of volunteer researchers was established to investigate the outbreak. A wide range of high-resolution techniques was used for different pathogens, including SARS-CoV-2 (RTq-PCR, ELISA and IHC), Toxoplasma gondii (IHC and IFA) and Escherichia coli (IFA), as well as a portable Metagenomic Sequencing utilizing Nanopore Technology. Within a span of four days after necropsies, we successfully identified T. gondii as the causative agent of this outbreak. This case highlights some of the obstacles faced with the current Brazilian surveillance system, which is still limited. A cross-platform interdisciplinary investigation could be a possible model for future epizootic investigations in non-human animals. Author summaryThe Brazilian epizootic surveillance system, under the regulation of the Ministry of Health, has been established to address a national list of compulsory notifiable diseases. However, focusing mainly on the risks to humans causes other zoonoses to be neglected. Here we present an outbreak that occurred during the first year of the COVID-19 pandemic that affected eleven neotropical primates (NP) belonging to six different species. Within four days of exhibiting a range of non-specific clinical signs, including fever, prostration, inappetence, and abdominal pain, ten NPs died. Despite testing negative for pathogens included in the national surveillance policy, a collaborative group of researchers investigated the outbreak in detail. Using integrated diagnostic techniques, we identified Toxoplasma gondii as the causative agent four days after necropsy. Toxoplasmosis causes devastating acute death outbreaks in neotropical primates and is currently absent in the national guidelines. This unified effort proved the effectiveness of a multidisciplinary collaborative surveillance network in facilitating precise diagnoses.

microbiology↗

A new field instrument for leaf volatiles reveals an unexpected vertical profile of isoprenoid emission capacities in a tropical forest

Both plant physiology and atmospheric chemistry are substantially altered by the emission of volatile isoprenoids (VI), such as isoprene and monoterpenes, from plant leaves. Yet, since gaining scientific attention in the 1950s, empirical research on leaf VI has been largely confined to laboratory experiments and atmospheric observations. Here, we introduce a new field instrument designed to bridge the scales from leaf to atmosphere, by enabling precision VI detection in real time from plants in their natural ecological setting. With a field campaign in the Brazilian Amazon, we reveal an unexpected distribution of leaf emission capacities (EC) across the vertical axis of the forest canopy, with EC peaking in the mid-canopy instead of the sun-exposed canopy surface, and high emissions occurring in understory specialist species. Compared to the simple interpretation that VI protect leaves from heat stress at the hot canopy surface, our results encourage a more nuanced view of the adaptive role of VI in plants. We infer that forest emissions to the atmosphere depend on the dynamic microenvironments imposed by canopy structure, and not simply on canopy surface conditions. We provide a new emissions inventory from 51 tropical tree species, revealing moderate consistency in EC within taxonomic groups. Our self-contained, portable instrument provides real-time detection and live measurement feedback with precision and detection limits better than 0.5 nmol m-2leaf s-1. We call the instrument PORCO based on the gas detection method: photoionization of organic compounds. We provide a thorough validation of PORCO and demonstrate its capacity to detect ecologically driven variation in leaf emission rates and thus accelerate a nascent field of science: the ecology and ecophysiology of plant volatiles. Type of paperMethod

plant biology↗