Schools reopening and the COVID-19 pandemic: a case study from Macaé, Rio de Janeiro, Brazil.

Since the first reported case of COVID-19 in Brazil, the public and private educational system started to close. Up to November 2020, scientific discussions about the return of schooling activities have been rarely performed by the national scientific community and police-makers. The great delay of school returning in Brazil contrasts with successful international strategies of school reopening worldwide and seems counterintuitive with the reopening of non-essential activities. Here, important issues to be considered before and during school reopening are reviewed and discussed. COVID-19 testing is essential to avoid disease spreading, but high cost of individual RT-qPCRs impairs an extensive testing strategy for school returning. To reduce costs and increase the speed of diagnosis, we tested the efficiency of a pooled-sample PCR strategy in a cohort of the educational staff in the city of Macaé/RJ, finding five asymptomatic individuals (0,66%) among the 754 people tested. Thus, a polled-sample PCR testing strategy of the educational staff might prevent infection spreading in schools at a reasonable cost. We discuss how our test strategy could be coupled with internationally recognized safety rules to allow for a safe school return and how countries from different world regions are dealing with educational activities during COVID-19 pandemic.

Forecasting the seasonal dynamics of Trichoplusia ni (Lep.: Noctuidae) on three Brassica crops through neural networks.

The cabbage looper, Trichoplusia ni Hübner (Lep.: Noctuidae), is a destructive pest of Brassica crops. Their larvae defoliate plants, leading to reduced crop yield. Understanding and modeling pest seasonal dynamics is central to management programs because it allows one to set up sampling and control efforts. This study aimed to train, with field-collected data, artificial neural networks (ANN) for T. ni forecasting on Brassica crops. ANNs were used due to their suitability to fit complex models with multiple predictors. Three weather variables (air temperature, rainfall, and relative humidity lagged at different intervals from the day of pest assessment) and three host plants (broccoli, cabbage, and cauliflower) along with another plant-related variable (days after transplanting) were used as input variables to build ANNs with different topologies. Two outputs (T. ni eggs or larvae) were tested to verify which one would yield more precise models. ANNs forecasting T. ni eggs performed better, based on Pearson's correlation (rv) of observed with fitted values. The winning ANN (rv = 0.706) had weather data lagged by 15 days, 2 neurons in the hidden layer, hyperbolic tangent as the activation function, and resilient propagation as the learning algorithm. Broccoli and cauliflower were the hosts with major contributions for T. ni occurrence. Rainfall was the primary environmental predictor and affected T. ni negatively. Therefore, the winning ANN may be used to forecast T. ni egg densities 15 days in advance, allowing for timely management of this pest.

Phylogenetics, patterns of genetic variation and population dynamics of Trypanosoma terrestris support both coevolution and ecological host-fitting as processes driving trypanosome evolution.

BACKGROUND: A considerable amount of evidence has favored ecological host-fitting, rather than coevolution, as the main mechanism responsible for trypanosome divergence. Nevertheless, beyond the study of human pathogenic trypanosomes, the genetic basis of host specificity among trypanosomes isolated from forest-inhabiting hosts remains largely unknown. METHODS: To test possible scenarios on ecological host-fitting and coevolution, we combined a host capture recapture strategy with parasite genetic data and studied the genetic variation, population dynamics and phylogenetic relationships of Trypanosoma terrestris, a recently described trypanosome species isolated from lowland tapirs in the Brazilian Pantanal and Atlantic Forest biomes. RESULTS: We made inferences of T. terrestris population structure at three possible sources of genetic variation: geography, tapir hosts and 'putative' vectors. We found evidence of a bottleneck affecting the contemporary patterns of parasite genetic structure, resulting in little genetic diversity and no evidence of genetic structure among hosts or biomes. Despite this, a strongly divergent haplotype was recorded at a microgeographical scale in the landscape of Nhecolândia in the Pantanal. However, although tapirs are promoting the dispersion of the parasites through the landscape, neither geographical barriers nor tapir hosts were involved in the isolation of this haplotype. Taken together, these findings suggest that either host-switching promoted by putative vectors or declining tapir population densities are influencing the current parasite population dynamics and genetic structure. Similarly, phylogenetic analyses revealed that T. terrestris is strongly linked to the evolutionary history of its perissodactyl hosts, suggesting a coevolving scenario between Perissodactyla and their trypanosomes. Additionally, T. terrestris and T. grayi are closely related, further indicating that host-switching is a common feature promoting trypanosome evolution. CONCLUSIONS: This study provides two lines of evidence, both micro- and macroevolutionary, suggesting that both host-switching by ecological fitting and coevolution are two important and non-mutually-exclusive processes driving the evolution of trypanosomes. In line with other parasite systems, our results support that even in the face of host specialization and coevolution, host-switching may be common and is an important determinant of parasite diversification.

Efficacy of parasitological methods for the diagnosis of Strongyloides stercoralis and hookworm in faecal specimens.

To compare the efficacy of stool examination for the detection of Strongyloides stercoralis and hookworm, a total of 634 stool samples from the routine laboratory service of the Pharmacia Faculty, Federal University of Bahia, Brazil, were examined by agar plate culture (APC), Baermann-Moraes and spontaneous sedimentation. The sensitivity of agar plate culture, calculated by combining results of all 3 methods, was 95% for S. stercoralis and 77.6% for hookwoorm. Moreover, APC had superior accuracy than Baermann-Moraes and spontaneous sedimentation for S. stercoralis and hookworm diagnosis, respectively. The S. stercoralis and hookworm positive samples from the laboratory routine, obtained after the previous analysis, along with those initially selected, were used to evaluate the concordance between microscopic examination and both the type of furrows left by larvae and the time for culture positivity using the APC method. Of 115 stool samples positive for S. stercoralis and 92 positive for hookworm, 110 (95.7%) and 89 (96.7%), respectively, had concordant results for furrows and morphological characteristics. The cumulative percentage of positivity increased to 94% by the third day of observation; at this time, only 19.6% of hookworm-positive samples had positive culture plates. Analyses of 74 S. stercoralis-positive stool samples stored at 4°C for 24, 48 and 72h showed the presence of larvae in 48.6%, 28.4% and 23% of samples, respectively when re-examined by the APC. As a definitive diagnosis of strongyloidiasis depends on the microscopic demonstration of parasites, increasing the sensitivity of the detection requires the use of different parasitological methods, including APC.

Survey of feline leukemia virus and feline coronaviruses in captive neotropical wild felids from Southern Brazil.

A total of 57 captive neotropical felids (one Leopardus geoffroyi, 14 Leopardus pardalis, 17 Leopardus wiedii, 22 Leopardus tigrinus, and three Puma yagouaroundi) from the Itaipu Binacional Wildlife Research Center (Refúgio Bela Vista, Southern Brazil) were anesthetized for blood collection. Feces samples were available for 44 animals, including one L. geoffroyi, eight L. pardalis, 14 L. wiedii, 20 L. tigrinus, and one P. yagouaroundi. Total DNA and RNA were extracted from blood and feces, respectively, using commercial kits. Blood DNA samples were evaluated by polymerase chain reaction (PCR) for feline leukemia virus (FeLV) proviral DNA, whereas reverse transcriptase-PCR was run on fecal samples for detection of coronavirus RNA. None of the samples were positive for coronaviruses. A male L. pardalis and a female L. tigrinus were positive for FeLV proviral DNA, and identities of PCR products were confirmed by sequencing. This is the first evidence of FeLV proviral DNA in these species in Southern Brazil.

Screening of antigenemia and isolation of Cryptococcus neoformans and C. gattii from cloaca and crop of birds in the state of Paraná, Brazil / Antigenemia e tentativa de isolamento de Cryptococcus neoformans e C. gattii a partir da cloaca e inglúvio de aves no Estado do Paraná

Cryptococcus neoformans and C. gattii are associated with dry bird excreta but rarely recovered from birds' digestive tract. The objective of the present study was (1) to verify the existence of C. neoformans and C. gattii in crop and cloaca of wildlife and captivity birds hypothesizing about a possible primary source of this yeast in the excreta, and (2) to determine the fungi's invasive capability in avian species through latex agglutination. For that purpose, 172 cloacal and 77 crop samples of domestic pigeon, Passerine, and Psittacine birds were collected. None of these samples was positive, suggesting that the yeast is not saprobiotic in the digestive tract of these birds. Only one out of 82 serum samples collected from pigeons and Psittacine birds was positive (title 1:2) showing that Cryptococcus sp. probably has a low invasive capability in birds, and is thus considered only a dry excreta colonizer.

Cryptococcus neoformans e C. gattii são frequentemente isolados de excretas de aves, entretanto ocorre pouca recuperação desse fungo a partir do trato gastrintestinal. Os objetivos desse estudo foram verificar a existência de C. neoformans e C. gattii no inglúvio e na cloaca de aves de vida livre e cativeiro, avaliando uma possível fonte primária desta levedura nas excretas e determinar a capacidade invasiva do fungo em aves por meio da aglutinação em látex. Para tanto, foram coletadas 172 amostras de cloaca e 77 de inglúvio de pombos- domésticos, Passeriformes e Psittaciformes. Nenhuma amostra se mostrou positiva, sugerindo-se que o fungo não é saprobiótico do aparelho digestório destas aves. Das 82 amostras de soro colhidas a partir de pombos-domésticos e Psittaciformes, somente uma obtida a partir de pombo-doméstico se mostrou positiva (titulação 1:2), demonstrando que Cryptococcus sp. apresenta baixa capacidade invasiva em aves, sendo, portanto, considerado somente um colonizador de excretas ressequidas.

Activity of systemic lupus erythematosus in end-stage renal disease patients: study in a Brazilian cohort.

BACKGROUND: Dialysis has been associated with lupus remission. We studied the prevalence of systemic lupus erythematosus (SLE) as a cause of end-stage renal disease (ESRD) in the metropolitan area of Rio de Janeiro and assessed disease activity in SLE patients on dialysis. METHODS: Of 3,535 ESRD patients, 63 had SLE (1.8%). Fifty-seven entered the study (54 females, 3 males, 38 +/- 10 years). Hemodialysis consisted of 3 sessions per week of about 4 h duration, blood flow of about 400 ml/min, bicarbonate dialysate ([Ca(2+)] = 2.5-3.5 mEq/l) at 500 ml/min and cellulose acetate or polysulfone dialyzers. Activity was initially defined as: non-renal (nr) SLE disease activity index (SLEDAI) of >0; use of at least 20 mg/day of prednisone; and/or any dose of another activity-controlling drug. Fifty-seven ESRD patients without SLE were used as controls. RESULTS: Eighteen SLE patients were under drug treatment; of the remaining, 30 had an nrSLEDAI of >0 totaling 48 patients (84%) initially labeled as active. An apparent activity was also present in 21 controls (37%). Of those, 19 had an nrSLEDAI of <4. With a cutoff of >or=4, figures in each group would be 49 and 4%. Under this criterion, age was the only significant predictor of flare in our SLE ESRD population in a multivariate logistic regression model. Activity remained high in patients who were on dialysis for >5 years (7/18, 39%). CONCLUSION: SLE accounted for 1.8% of our ESRD patients. Application of SLEDAI to dialysis patients may require consideration of confounding factors related to the ESRD state. Even with a score of >or=4 as a cutoff, SLE activity in dialysis patients was high (49%) and long-lasting. Age was the major determinant of flare.