Seasonal occurrence and variation of ectoparasites in Nile tilapia (Oreochromis niloticus) in the Federal District, Brazil

The present study assesses the diversity and seasonal variation of parasites in Oreochromis niloticus (Nile tilapia) cultivated in excavated tanks in the Federal District, Brazil. A total of 120 specimens of O. niloticus were collected in 12 monthly collections. Water quality parameters were checked at all tanks. The animals, sacrificed by immersion into anesthetic solution, had the gills scraped, in which the mucus was analyzed under an optical microscope. Parasitological examination showed Trichodina sp., Epistylis sp., Ichthyophthirius multifiliis, and Monogenea helminths in the fish gills. We found statistically significant differences between Monogenea parasites collected in the fall and winter and between I. multifiliis protozoans collected in fall-winter and winter-summer periods. Except for Epistylis sp., all parasites showed abundance peaks in O. niloticus specimens collected during the winter, which may characterize the seasonality of these parasites in the Federal District region. Monogenea helminths were the most prevalent among the parasites found, with the highest prevalence during the fall. The mean abundance of parasites was similar between the fall and winter. However, the abundance of monogenetic trematodes was higher between the winter and summer. I. multifiliis showed significant variation between fall-winter and winter-summer periods.(AU)

Serological detection of Brazilian Spotted-Fever Group Rickettsiae in horses in Brasília, Federal District, Brazil / Detecção sorológica de Rickettsiae do grupo da Febre Maculosa Brasileira em cavalos de Brasília, Distrito Federal, Brasil

Brazilian spotted fever (BSF) is a zoonosis caused by spotted-fever group Rickettsiae that is transmitted to humans through tick bites. Dogs and horses are considered to be sentinel animals for this disease. In this study, a serological survey was carried out among horses apprehended by the governmental animal control service of the Federal District, Brazil. Serum samples were obtained from 122 horses over a one-year period. Through the indirect immunofluorescence antibody assay (IFA) for Rickettsia rickettsii anti-IgG antibodies, 21 samples were found to be positive, with titers ranging from 1:64 to 1:512. This demonstrates that the agent presents silent circulation in the Federal District.

A febre maculosa brasileira (FMB) é uma zoonose causada por riquétsias do Grupo da Febre Maculosa transmitida ao homem através de picadas de carrapatos. Cães e cavalos são considerados animais sentinelas para essa doença. Neste estudo, foi realizado inquérito sorológico em cavalos apreendidos pelo serviço governamental de controle de animais do Distrito Federal, Brasil. Os soros utilizados foram obtidos de 122 cavalos, coletados por conveniência pelo período de um ano. Através do ensaio de imunofluorescência indireta (IFA) para anticorpos anti-IgG contra Rickettsia rickettsii, 21 amostras foram positivas para títulos variando de 1:64 a 1:512, demonstrando a circulação silenciosa do agente no Distrito Federal.

Situation of and phenotypic markers of susceptibility to helminth infection among sheep on farms in the Brazilian cerrado biome / Diagnóstico de situação e marcadores fenotípicos das parasitoses gastrintestinais em ovinos de fazendas localizadas no Distrito Federal: bioma cerrado brasileiro

This study aimed to determine the intensity, seasonality, and distribution by genera of, as well as to identify phenotypic markers of susceptibility to, gastrointestinal parasites among sheep on farms within the Brazilian savanna (cerrado) biome. We evaluated 1271 sheep, on seven farms, during the rainy season (in December 2017 and December 2018) and dry season (in July 2018 and July 2019). Parasitological evaluation was based on culture and EPG. We calculated hematocrit, as well as the body condition score and feces score. Of the sheep evaluated, 34.15% had moderate-to-severe parasitic infection. The factors of herds phenotypic characterization about helminth infections were (p 0.05 for all): anemia (OR = 5.72); leanness (OR = 1.80); loose stools or diarrhea (OR = 1.54); breed other than Santa Inês (OR = 2.31); weaned lamb category (OR = 4.76); lambing ewe category (OR = 4.66); and dry season (OR = 2.37). Haemonchus, Trichostrongylus, Oesophagostomum, and Cooperia accounted for 76.40%, 20.23%, 2.89%, and 0.47%, respectively, of the helminth genera identified, with their proportional distributions being comparable between the rainy and dry seasons. Changes in health management, with regard to helminth infection control, are urgently needed in order to combat the disease more effectively and sustainably.(AU)

A presente pesquisa objetivou determinar a intensidade, sazonalidade, predominância de gêneros e marcadores fenotípicos às parasitoses gastrointestinais em fazendas de criação de ovinos do Distrito Federal, no bioma cerrado brasileiro. Foram avaliados 1.271 ovinos oriundos de sete propriedades, durante os períodos chuvoso (dezembro de 2017 e dezembro de 2018) e seco (julho de 2018 e julho de 2019). Procedeu-se a avaliação parasitológica por coprocultura e OPG, dosagem de hematócrito, escore de condição corporal e de fezes. Dos indivíduos avaliados, 34,15% deles apresentaram infecção parasitária moderada a grave. Os fatores de caracterização fenotípica dos rebanhos quanto às infecções helmínticas (p 0,05), foram: anemia (OR = 5,72),magreza (OR = 1,80), fezes pastosas/diarreicas (OR = 1,54), raças distintas à raça Santa Inês (OR = 2,31), categorias de produção animal jovens (OR = 4,76) e fêmeas paridas (OR = 4,66), e período seco (OR = 2,37). Haemonchus, Trichostrongylus, Oesophagostomum e Cooperia foram os gêneros de helmintos observados nas seguintes proporções: 76,40%, 20,23%, 2,89% e 0,47%, respectivamente, sem distinção em sua distribuição entre os períodos chuvoso e seco. Mudanças no manejo sanitário com relação às helmintoses são urgentemente necessárias, para um controle da doença de forma mais eficaz e sustentável.(AU)

Parasitic lesions in fish in the Federal District, Brazil

Brazil has a vast territory and favorable climatic conditions that allow the cultivation of freshwater fish. The intensification of the productive system can cause an imbalance in the aquatic environment as a result of poor water quality, nutritional deficiencies and infectious or parasitic diseases. The laboratory diagnosis and the determination of the prevalence of the main lesions, which occur in a certain region, help to guide towards the etiological diagnosis. This study aimed to describe the main parasitic lesions in fish in the routine at the Veterinary Pathology Laboratory of the Universidade de Brasília (UnB). All records of fish with parasitic lesions were recovered. Those cases in which there was an intralesional parasite and which presented lesions compatible with the parasite were included. The screening of ectoparasites was done by scraping the superficial mucus from the gills and skin. Organ sections were routinely processed for histopathologyand stained with hematoxylin-eosin (HE). In some records, parasitological identification was carried. The information was divided into the species of the affected fish, epidemiology of the outbreak (water quality, temperature, type of breeding), lesion distribution, etiology and macroscopic and microscopic changes. The resulting data was organized in absolute frequency and percentage. In this study, 22 cases were counted, between individual deaths and outbreaks, totaling 83 necropsied teleost fish. Inflammatory changes of parasitic origin were seen in 13/22 (59%) of the cases had lesions of parasitic origin. Skin lesions and gills were the most relevant. Macroscopically, red areas or spots of hyperemia or hemorrhage on the body surface were the most prevalent findings. Under microscopy, proliferative gill inflammation was the most relevant diagnosis. Pscinoodinium pilullare (Dinoflagellida), Ichthyophthirius multifiliis (Ciliophora), and monogenetic worms (Monogenea) were the main parasites found. Trichodina sp. (Ciliophora), Ichtyobodo sp. (Kinetoplastida), Amoebas, and Chilodonella sp. (Ciliophora), were seen in fewer numbers. An unusual case suggestive of parasitism by Eustrongylides sp. (Nematoda), in a pirá-brasília (Simpsonichthys boitonei), specimen has been recorded. The diagnoses were based on epidemiology, anatomopathological and parasitological findings. The most frequent and significantly lethal lesion in the study was proliferative and / or hyperplastic branchitis. Proliferative branchitis with lamellar epithelial hyperplasia (LEH) is a response to some type of chemical or mechanical injury to the gill epithelium in order to protect the capillaries from further damage or microbial penetration. However, it also increases the diffusion distance between capillaries and the environment and, therefore, hinders breathing, excretory and osmoregulatory functions. Protozoan infections and monogenetic worms in general generated LEH and skin lesions of mechanical origin. Secondary bacterial infection, were observed in this parasitosis determining the cause of death of the fish. Its pathogenicity comes from the lesions caused by the colonization and histophagy of the epithelial surfaces, mainly gills and skin, causing epithelial proliferation, lamellar cell fusion, epithelial cell degeneration and necrosis forming several ulcers in the epithelium after the release of mature trophies. The pathogenesis of parasitism by Eustrongylides spp. is considerable when there is a large quantity of these larvae that can cause intestinal obstruction, rupture and compression of viscera, of greater importance in small fish. The main parasites of necropsied fish were protozoa and monogenetic worms, which mainly cause branquitis and dermatitis in varying grades.(AU)