Ornithonyssus sylviarum (Acari: Macronyssidae) parasitism among poultry farm workers in Minas Gerais state, Brazil / Parasitismo de Ornithonyssus sylviarum (Acari: Macronyssidae) em trabalhadores de avicultura no Estado de Minas Gerais, Brasil

ABSTRACT: Ornithonyssus sylviarum is a hematophagous mite present in wild, domestic, and synanthropic birds. However, this mite can affect several vertebrate hosts, including humans, leading to dermatitis, pruritus, allergic reactions, and papular skin lesions. This study evaluated the epidemiological characteristics of O. sylviarum attacks on poultry workers, including data on laying hens, infrastructure and management of hen houses, and reports of attacks by hematophagous mites. In addition, a case of mite attack on a farm worker on a laying farm in the Midwest region in Minas Gerais is presented. It was found that 60.7% farm workers reported attacks by hematophagous mites. Correspondence analysis showed an association between reports of mite attacks in humans with (1) presence of O. sylviarum in the hen house, (2) manual removal of manure by employees, and (3) history of acaricide use. The specimens collected from the location were confirmatively identified as O. sylviarum. O. sylviarum attacks ave not been reported when manure was removed in a shorter time interval and did not use acaricide in the sheds when the removal was done by manure conveyor belt. Parasitism by O. sylviarum should be considered a relevant occupational hazard affecting employees working in direct contact with commercial egg-laying hens in Minas Gerais. We emphasized the need to monitor hen infestations by this mite to improve the development of mite control strategies.

RESUMO: Ornithonyssus sylviarum é um ácaro hematófago de aves silvestres, domésticas e sinantrópicas. No entanto, este ácaro pode afetar vários hospedeiros vertebrados, incluindo humanos, levando a dermatites, prurido, reações alérgicas e lesões cutâneas papulosas. O presente estudo avaliou os aspectos epidemiológicos do ataque de O. sylviarum em trabalhadores de granjas avícolas e descreveu um relato de caso em uma granja de postura. Este estudo utilizou um banco de dados secundário com informações sobre as poedeiras, infraestrutura e manejo dos galinheiros e relatos de ataques por ácaros hematófagos. Foi apresentado um caso de ataque de ácaro a um trabalhador rural no Centro-Oeste em Minas Gerais. Houve uma frequência de 60,7% de trabalhadores que relataram ter sido atacados por ácaros hematófagos em fazendas. A análise de correspondência mostrou uma associação entre relatos de ataques de ácaros em humanos com (1) presença de O. sylviarum na fazenda, (2) remoção manual de esterco por funcionários da fazenda e (3) histórico de uso de acaricidas. Os espécimes coletados do local foram identificados como O. sylviarum. Não há ataques de O. sylviarum, quando a remoçãodo esterco é feita em menor intervalo de tempo, e não se utiliza acaricida nos galpões quando a remoção é feita por esteira transportadora de esterco. Conclui-se que o parasitismo por O. Sylviarum deve ser considerado como um risco ocupacional relevante, que afeta trabalhadores que trabalham diretamente com poedeiras comerciais em Minas Gerais. Ressaltamos a necessidade de monitorar as infestações de aves por esse ácaro, a fim de melhorar o desenvolvimento de estratégias de controle.

Epidemiological characterization and risk evaluation associated with the presence of Phthirapterain poultry farms from Minas Gerais, Brazil

Phthirapteraare lice highly adapted to living as permanent and obligatory ectoparasites of birds and mammals. High infestations by biting lice contribute to the low productivity, loss quality of the eggs, besides weight decrease of chickens. Therefore, this study aimed to evaluate and to characterize the risks involved with the presence of biting lice in laying chicken from Minas Gerais, Brazil, throught a Multiple Correspondence Analysis (MCA). A secondary database with information regarding 402 chicken houses from 42 properties of laying hens from the same region was used and adapted for this study. The variables that composed the correspondence model were selected through Chi-square tests (p ≤ 0.05). A risk index was designed to relate the presence of biting lice out of variables such as risk factors related to the presence of these ectoparasites. The MCA graphic designed to conduct the epidemiological characterization of the presence of biting lice presented a Chi-square accumulated value of 53.59%. There was an association between the risk index and the synanthropic birds, subsistence hens, presence of lice and other ectoparasites in shelters and ectoparasites control. These results provide knowledge about the Phthirapteraepidemiology. Besides that, this information may contribute to the decision-making process in order to reduce the risk of possible infestations in poultry farms and the negative effects of the infestations.

Prevalence and risk factors for viral exposure in rural dogs around protected areas of the Atlantic forest.

BACKGROUND: Despite the crucial role of domestic dogs as reservoirs for zoonosis and some of the most threatening diseases for wild carnivores such as distemper and parvovirosis, little is known about the epidemiological features and the risk factors involved in pathogen exposure of dogs that live in human/wildlife interfaces and actually contacts wildlife. Through a cross-sectional serological approach and questionnaire survey, we assessed the prevalence along with individual and environment-associated risk factors for four important viral diseases of rural dogs living in households around six Atlantic Forest fragments in southeast Brazil. RESULTS: Widespread exposure to canine parvovirus (97%), canine distemper virus (15%) and canine adenovirus (27%) was detected, but none for canine coronavirus. Dogs from small private reserves were more exposed to parvovirus and canine distemper virus than those from larger state parks. Exposure was associated with dog sex and age, lack of health care and the number of people in the households. Remarkably, factors linked to free-ranging behaviour of dogs were associated with the exposure for all pathogens detected. CONCLUSIONS: According to identified associations, reducing viral pathogen exposure in dogs will require inhibiting dog's movements and access to nearby forests and villages and improving veterinary assistance. Promoting dog vaccination and population control through sterilization around protected areas is also necessary. The study provides support for preventive management actions aimed to protect the health of rural dogs, and consequently of Atlantic Forest's wild carnivores.

Water-soluble nanoconjugates of quantum dot-chitosan-antibody for in vitro detection of cancer cells based on "enzyme-free" fluoroimmunoassay.

Cancer remains one of the world's most devastating diseases with millions of fatalities and new cases every year. In this work, we attempted to develop a facile "enzyme-free" fluoroimmunoassay based on the novel nanoconjugates composed of CdS quantum dots (QDs) as the fluorescent inorganic core and an antibody-modified polysaccharide as the organic shell, modeling their possible application for the in vitro diagnosis of non-Hodgkin lymphoma (NHL) cancer. Chitosan was conjugated with an anti-CD20 polyclonal antibody (pAbCD20) by the formation of covalent amide bonds. In the sequence, these chitosan-antibody conjugates were utilized as direct ligands for the surface biofunctionalization of CdS QDs (CdS/chitosan-pAbCD20) using a single-step colloidal process in aqueous medium at room temperature. The most relevant physico-chemical properties of these nanoconjugates were assessed by morphological and spectroscopic techniques. The results indicated that CdS nanocrystals were produced with an average diameter of 2.5 nm and with cubic zinc blende crystalline nanostructure. The CdS-immunoconjugates (CdS/chitosan-pAbCD20) presented colloidal hydrodynamic diameter (HD) of 15.0 ± 1.2n m. In addition, the results evidenced that the "enzyme-free" QD-linked immunosorbent assay (QLISA) was effective for the in vitro detection against the antigen CD20 (aCD20) based on fluorescent behavior of the CdS nanoconjugates. Moreover, the CdS-immunoconjugates were successfully used for fluorescence bioimaging of NHL cancer cells. Finally, the cell viability results using different cell cultures based on LDH, MTT and Resazurin bio-assays have demonstrated no cytotoxicity of the new CdS-chitosan bioconjugates relative to the standard controls. Thus, CdS conjugates may offer a promising platform for the future development of in vitro and in vivo applications for the detection and diagnosis of NHL cancer cells.

Fluorescent nanohybrids based on quantum dot-chitosan-antibody as potential cancer biomarkers.

Despite undeniable advances in medicine in recent decades, cancer is still one of the main challenges faced by scientists and professionals in the health sciences as it remains one of the world's most devastating diseases with millions of fatalities and new cases every year. Thus, in this work, we endeavored to synthesize and characterize novel multifunctional immunoconjugates composed of quantum dots (QDs) as the fluorescent inorganic core and antibody-modified polysaccharide as the organic shell, focusing on their potential applications for in vitro diagnosis of non-Hodgkin lymphoma (NHL) cancer tumors. Chitosan was covalently conjugated with anti-CD20 polyclonal antibody (pAbCD20) via formation of amide bonds between amines and carboxyl groups. In the sequence, these biopolymer-antibody immunoconjugates were utilized as direct capping ligands for biofunctionalization of CdS QDs (CdS/chitosan-pAbCD20) using a single-step process in aqueous medium at room temperature. The nanostructures were characterized by UV-vis spectroscopy, photoluminescence spectroscopy (PL), FTIR, and transmission electron microscopy (TEM) with selected area electron diffraction. The TEM images associated with the UV-vis optical absorption results indicated formation of ultrasmall nanocrystals with average diameters in the range of 2.5-3.0 nm. Also, the PL results demonstrated that the immunoconjugates exhibited "green" fluorescent activity under ultraviolet excitation. Moreover, using in vitro laser light scattering immunoassay (LIA), the QDs/immunoconjugates have shown binding affinity against antigen CD20 (aCD20) expressed by lymphocyte-B cancer cells. In summary, innovative fluorescent nanoimmunoconjugate templates were developed with promising perspectives to be used in the future for detection and imaging of cancer tumors.