Host-parasite interactions in perpetual darkness: Macroparasite diversity in the cavefish Astyanax mexicanus.

Astyanax mexicanus has repeatedly colonized cave environments, displaying evolutionary parallelisms in many troglobitic traits. Despite being a model system for the study of adaptation to life in perpetual darkness, the parasites that infect cavefish are practically unknown. In this study, we investigated the macroparasite communities in 18 cavefish populations from independent lineages and compared them with the parasite diversity found in their sister surface fish populations, with the aim of better understanding the role that parasites play in the colonization of new environments. Within the cavefish populations, we identified 13 parasite taxa, including a subset of 10 of the 27 parasite taxa known for the surface populations. Parasites infecting the cavefish belong to five taxonomic groups, including trematodes, monogeneans, nematodes, copepods, and acari. Monogeneans are the most dominant group, found in 14 caves. The macroparasites include species with direct life cycles and trophic transmission, including invasive species. Surprisingly, paired comparisons indicate higher parasite richness in the cavefish than in the surface fish. Spatial variation in parasite composition across the caves suggests historical and geographical contingencies in the host-parasite colonization process and potential evolution of local adaptations. This base-line data on parasite diversity in cavefish populations of A. mexicanus provides a foundation to explore the role of divergent parasite infections under contrasting ecological pressures (cave vs. surface environments) in the evolution of cave adaptive traits.

The macroparasite fauna of cichlid fish from Nicaraguan lakes, a model system for understanding host-parasite diversification and speciation.

The Nicaraguan lakes represent an ideal continent-island-like setting to study the colonization patterns of both fish and their parasites. The dominant fish fauna are cichlids, particularly the Midas cichlid species complex Amphilophus spp., a well-studied model for recent sympatric speciation. Here, we characterized the Midas cichlid macroparasite diversity in Nicaraguan lakes. We evaluated patterns of parasite diversity across host populations. Morphological and molecular analyses were conducted, revealing a macroparasite fauna composed by 37 taxa, including platyhelminths, nematodes, copepods, branchiurans, hirudineans and oribatids. Three invasive species are reported for the first time. The Midas cichlid was infected by 22 parasite taxa, 18 shared with other cichlids. Eight taxa conformed the core parasite fauna of the Midas cichlid. The large lakes had higher parasite diversity than the smaller and isolated crater lakes, although parasite infracommunity diversity was lower. Environmental factors along with the differential distribution of intermediate hosts, the potential resistance gained by their hosts after colonization of new lakes, competitive exclusion among parasites, or the introduction of exotic fish, may determine the observed pattern of parasite heterogeneous distribution. Our study provides a ground to explore the evolutionary history of both, hosts and parasites within the context of speciation and diversification processes.

Taxonomic assessment of the genus Procamallanus (Nematoda) in Middle American cichlids (Osteichthyes) with molecular data, and the description of a new species from Nicaragua and Costa Rica.

Procamallanus is a species-rich genus of parasitic nematodes of marine, brackish, and freshwater fishes, occurring also occasionally in amphibians and reptiles. In the Neotropical region, this genus is highly diverse, with species described from a wide range of fish families. In this study, we reassess the taxonomic status of Procamallanus rebecae with molecular and morphological data and describe a new species endemic to Nicaragua and Costa Rica. We analyzed all Procamallanus isolated from fish from the Nicaraguan lakes and some rivers in Costa Rica after an exhaustive analysis of their freshwater fish endoparasite fauna. Procamallanus rebecae is a host-specific parasite of Middle American cichlids, previously reported in southern Mexico, Nicaragua, and Costa Rica. We therefore compared these Central American specimens with individuals of P. rebecae collected in cichlids from southeastern Mexico using two genomic regions (28S rDNA and mitochondrial cytochrome oxidase subunit 1, COI). We found high levels of sequence divergence between Procamallanus from the two geographical regions, with up to 9.8 and 10.5% for both genetic markers, respectively. We also analyzed their morphology and found conspicuous differences in the shape of the mouth and the structure of the female cauda. We therefore describe the specimens of Procamallanus from Central American cichlids as a new species. Both Procamallanus species occur in different cichlid species and are allopatrically distributed. The host specificity and ancient association patterns between cichlids and Procamallanus and the jointly colonization of both hosts and parasites during their northern dispersal from South America are briefly discussed.

Clinical characteristics and outcomes among hospitalized adults with severe COVID-19 admitted to a tertiary medical center and receiving antiviral, antimalarials, glucocorticoids, or immunomodulation with tocilizumab or cyclosporine: A retrospective observational study (COQUIMA cohort).

BACKGROUND: The COVID-19 outbreak challenges the Spanish health system since March 2020. Some available therapies (antimalarials, antivirals, biological agents) were grounded on clinical case observations or basic science data. The aim of this study is to describe the characteristics and impact of different therapies on clinical outcomes in a cohort of severe COVID-19 patients. METHODS: In this retrospective, single-center, observational study, we collected sequential data on adult patients admitted to Hospital Universitario Quironsalud Madrid. Eligible patients should have a microbiological (positive test on RT-PCR assay from a nasal swab) or an epidemiological diagnosis of severe COVID-19. Demographic, baseline comorbidities, laboratory data, clinical outcomes, and treatments were compared between survivors and non-survivors. We carried out univariate and multivariate logistic regression models to assess potential risk factors for in-hospital mortality. FINDINGS: From March 10th to April 15th, 2020, 607 patients were included. Median age was 69 years [interquartile range, {IQR} 22; 65% male). The most common comorbidities were hypertension (276 [46·94%]), diabetes (95 [16·16%]), chronic cardiac (133 [22·62%]) and respiratory (114 [19·39%]) diseases. 141 patients (23·2%) died. In the multivariate model the risk of death increased with older age (odds ratio, for every year of age, 1·15, [95% CI 1·11 - 1·2]), tocilizumab therapy (2·4, [1·13 - 5·11]), C-reactive protein at admission (1·07, per 10 mg/L, [1·04 - 1·10]), d-dimer > 2·5 µg/mL (1·99, [1·03 - 3·86]), diabetes mellitus (2·61, [1·19 - 5·73]), and the PaO2/FiO2 at admission (0·99, per every 1 mmHg, [0·98 - 0·99]). Among the prescribed therapies (tocilizumab, glucocorticoids, lopinavir/ritonavir, hydroxychloroquine, cyclosporine), only cyclosporine was associated with a significant decrease in mortality (0·24, [0·12 - 0·46]; p<0·001). INTERPRETATION: In a real-clinical setting, inhibition of the calcineurin inflammatory pathway, NF-κΒ, could reduce the hyperinflammatory phase in COVID-19. Our findings might entail relevant implications for the therapy of this disease and could boost the design of new clinical trials among subjects affected by severe COVID-19. FUNDING: Hospital Universitario Quironsalud Madrid. Own fundings for COVID-19 research.

Acusicola margulisae n. sp. (Copepoda: Ergasilidae) from freshwater fishes in a Nicaraguan crater lake based on morphological and molecular evidence.

The ergasilid copepod Acusicola margulisae n. sp. is described based on material from three species of cichlid, Amphilophus citrinellus (Günther), Parachromis managuensis (Günther), and Oreochromis sp., and from the poecilid Poecilia mexicana (Steindachner), in the crater Lake Asososca León, Nicaragua. This constitutes the 15th species described in the genus Acusicola Cressey, 1970. The new species differs from all its congeners by the relatively longer first endopodal segment of leg 1, and the size and number of setae on second endopodal segment of leg 1. We provide the first gene sequence for a species of Acusicola. To examine the intraspecific genetic variation of the new species collected from different host species, sequences of the mitochondrial barcode region cox1 were generated. In addition, partial regions of the 18S and 28S ribosomal RNA genes were sequenced and used to infer the phylogenetic relationships of the genus Acusicola within the family Ergasilidae Burmeister, 1835. The phylogenetic trees yielded the isolates of Acusicola margulisae n. sp. as a reciprocally monophyletic lineage, and as the sister taxa of five genera of ergasilid copepods. The genus Ergasilus von Nordmann, 1832 was recovered as a paraphyletic group. These analyses indicate that phylogenetic relationships are not yet well resolved and more representative species and genera of the family are required to provide a robust classification of this highly diverse group of copepods.

Factores de riesgo en población no VIH con tuberculosis en Uruguay / Risk factors in non-HIV population with tuberculosis in Uruguay / Fatores de risco na população não-HIV com tuberculose no Uruguai

Resumen: Objetivo: Describir las características de la población de personas de 18 años o más con tuberculosis (TB) no coinfectadas con Virus de la Inmunodeficiencia Humana (VIH) en Uruguay en el período del 1 de enero de 2016 al 31 de diciembre de 2017. Métodos: Se obtuvieron los datos de la base de datos anonimizada del registro nacional de TB perteneciente a la Comisión Honoraria de Lucha Antituberculosa y Enfermedades Prevalentes (CHLA-EP) para todos los casos de TB bacteriológicamente confirmada en el período del 1/1/16 al 31/12/17. Se excluyó a todos los individuos menores de 18 años y a todos aquellos con diagnóstico positivo para el VIH. Se clasificó a dichos individuos según el sector del sistema de salud de pertenencia. Se analizó la frecuencia y proporción de variables reconocidas como vinculadas a la enfermedad para cada subgrupo. Resultados: Se registraron 1129 casos. La tasa de incidencia de TB para la población de 18 años o más no infectada por el VIH fue de de 21,8 casos cada 100.000 habitantes para el año 2016. Se observó una proporción de factores de riesgo relacionados al medio socioeconómico de 43,8% del total de la población; estos predominaron en el sector público con un 57,4%. La pérdida de seguimiento para el sector público fue de 12,8%, mientras que en el sector privado fue de 3,0%. Se vió un porcentaje de fallecimiento de 38,8% entre los desocupados. Conclusiones: Los factores de riesgo socioeconómicos predominaron en el sector público de salud. Dentro de estos, la desocupación fue la de mayor proporción y se asoció con mayor porcentaje de fallecimiento y pérdida de seguimiento como resultado de tratamiento con respecto a la población general. La mayoría de los casos presentaron la forma pulmonar, y dentro de la extrapulmonar la más frecuente fue la pleural.

Abstract. Objective: To describe the characteristics of the population with tuberculosis (TB), over the age of 18, without HIV infection in Uruguay in the period between January 1st, 2016 and December 31st, 2017. Methods: Data of TB cases confirmed by sputum culture between 1/1/16 and 12/31/17 was obtained from the anonymized data base of the national register of TB, which belongs to CHLA-EP. Individuals younger than 18 or with HIV infection were excluded. Patients included in this study were organized in two groups according to the following criteria: belonging to public health care and belonging to private health care. Frequency and proportion of different variables related to TB were analyzed in those groups. Results: 1129 cases were analyzed. The incidence rate of TB amongst the population of non-HIV uruguayans over the age of 18 was 21.8 per 100,000 in 2016. Risk factors related to socioeconomic status were observed in a proportion of 43.8% of the total population; these were more prevalent within the subpopulation that received public health care, with a proportion of 57.4%. Loss of follow-up for the public health care sector was seen in 12.8% of cases, while the private sector presented 3.0%. The percentage of death among the unemployed was of 38.8%. Conclusion: Socioeconomic risk factors were predominantly superior among patients belonging to public health services. Moreover, unemployment was the most frequent factor within that category, and those who presented this factor had higher percentage of death and loss of follow up as the final outcome of treatment, compared to the general population. Pulmonary tuberculosis was the most frequent clinical form, followed by tuberculosis pleurisy as the main form of extra pulmonary tuberculosis.

Resumo: Objetivo: Descrever as características da população de 18 anos ou mais de idade com tuberculose (TB) não co-infectada pelo Vírus da Imunodeficiência Humana (HIV) no Uruguai no período de 1 de janeiro de 2016 a 31 de dezembro de 2017. Métodos: Os dados foram obtidos do banco de dados anonimizado do registro nacional de TB pertencente à Comissão Honorária de Tuberculose e Doenças Prevalentes (CHLA-EP) para todos os casos de TB bacteriologicamente confirmada no período de 1/1/16 a 31/12/17. Todos os indivíduos com menos de 18 anos e todos com diagnóstico positivo de HIV foram excluídos. Esses indivíduos foram classificados de acordo com o setor do sistema de saúde dos membros. A frequência e proporção de variáveis reconhecidas como ligadas à doença para cada subgrupo foram analisadas. Resultados: 1129 casos foram registrados. A taxa de incidência de TB na população de 18 anos ou mais de idade não infectada pelo HIV foi de 21,8 casos por 100.000 habitantes até 2016. Foi observada uma proporção de fatores de risco relacionados ao ambiente socioeconômico de 43,8. % da população total; estes predominaram no setor público com 57,4%. A perda de acompanhamento para o setor público foi de 12,8%, enquanto no setor privado foi de 3,0%. Uma taxa de mortalidade de 38,8% foi observada entre os desempregados. Conclusões: Os fatores de risco socioeconômico predominaram no setor de saúde pública. Entre eles, o desemprego foi a maior proporção e foi associado a um maior percentual de óbitos e perda de seguimento como resultado do tratamento em relação à população em geral. A maioria dos casos apresentava a forma pulmonar e, na extrapulmonar, a mais frequente era a pleural.

Taxonomic status of Rhabdochona ictaluri (Nematoda: Rhabdochonidae) based on molecular and morphological evidence.

The genus Rhabdochona includes more than 100 species infecting freshwater fishes in all zoogeographical regions of the world. In Mexico, 12 nominal species of Rhabdochona have been recorded. Of these, Rhabdochona ictaluri was originally described as a parasite of endemic catfishes of the family Ictaluridae; however, the species was later considered on morphological grounds as a junior synonym of Rhabdochona kidderi. In this study, newly sampled specimens of R. ictaluri were obtained from the type host and type locality and were used to perform a detailed morphological analysis and molecular phylogenetic inferences through one mitochondrial and two nuclear genes; data were used in an integrative taxonomy context to test the taxonomic status of R. ictaluri. This approach proved to be very useful to confirm the validity of this species, and robust species limits were established between these two putative species considering morphology, molecular data, host association, and biogeography.