Eosinophilic meningitis is a disease characterized by increased eosinophils in the cerebrospinal fluid (CSF), which is the most commonly caused by invasion of the central nervous system by helminths, as occurs in Angiostrongylus cantonensis infections. The rodent Rattus norvegicus is the definitive natural host and humans act as accidental hosts and can become infected by eating raw or undercooked snails or food contaminated with infective L3 larvae. Recently in Brazil there have been four cases of eosinophilic meningitis due to ingestion of infected Achatina fulica. To evaluate biochemical and histopathological changes caused by this parasite, R. norvegicus were experimentally infected with 100 L3 larvae of A. cantonensis. After the anesthetic procedure, serum from the rodents was collected from the inferior vena cava for evaluation of the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALKP), gamma-glutamyl transferase (GGT), total protein and its fractions. During the necropsy, the liver was collected and weighed. Then a 1-g fragment was extracted from the major lobe to quantify the hepatic glycogen and fragment remainder was taken from the same lobe and fixed in Milloning's formalin for histopathological examination. Additionally, helminths were collected from the brain and lungs of the rodents. The activities of AST, ALT, ALKP and GGT in the serum and hepatic glycogen increased in response to infection, while the levels of globulin and total protein increased only in the eighth week of infection and there was a reduction in the levels of serum glucose. Albumin and bilirubin concentrations remained stable during the experiment. Infection with A. cantonensis caused metabolic and histopathological changes in the rodents. This study can contribute to a better understanding of the relationship between A. cantonensis and R. norvegicus.
Some terrestrial gastropods are agricultural pests and are exposed to toxic products capable of causing physiological and biological alterations. The action of some herbicides and molluscicides has been studied on freshwater snails, but there are few studies of terrestrial species. This study analyzed the biological and physiological responses of Bulimulus tenuissimus exposed to the natural molluscicidal latex of Euphorbia milii var. hislopii and the synthetic herbicide Roundup® Original. A total of 210 snails were divided and exposed for 24 hours to the products (latex or herbicide in concentrations of 1,000 ppm and 100,000 ppm) and type 2 water. Of this total, 150 exposed animals were analyzed biochemically after 24 hours, and the others were observed during 30 days for analysis of the mortality rate. After 24 hours, some snails presented escape mechanisms such as epiphragm formation, cephalopedal mass retraction and burial. The latex did not cause metabolic alterations but the herbicide altered the carbohydrate metabolism of B. tenuissimus, reducing energy substrates in the sites analyzed (hemolymph, digestive gland and cephalopedal mass). Regarding the protein metabolism, there was no alteration after exposure to both analyzed substances. After 30 days of exposure, higher mortality was recorded for the groups exposed to the herbicide. These findings suggest that B. tenuissimus is resistant to the molluscicidal latex of Euphorbia milii var. hislopii more than the herbicide Roundup® Original.
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