Development of Hepatozoon caimani (Carini, 1909) Pessôa, De Biasi & De Souza, 1972 in the Caiman Caiman c. crocodilus, the Frog Rana catesbeiana and the Mosquito Culex fatigans

The sporogony of Hepatozoon caimani has been studied, by light microscopy, in the mosquito Culex fatigans fed on specimens of the caiman Caiman c. crocodilus showing gametocytes in their peripheral blood. Sporonts iniciate development in the space between the epithelium of the insect gut and the elastic membrane covering the haemocoele surface of the stomach. Sporulating oocysts are clustered on the gut, still invested by the gut surface membrane. Fully mature oocysts were first seen 21 days after the blood-meal. No sporogonic stages were found in some unidentified leeches fed on an infected caiman, up to 30 days following the blood-meal. When mosquitoes containing mature oocysts were fed to frogs (Leptodactylus fuscus and Rana catesbeiana), cysts containing cystozoites developed in the internal organs, principally the liver. Feeding these frogs to farm-bred caimans resulted in the appearance of gametocytes in their peripheral blood at some time between 59 and 79 days later, and the development of tissue cysts in the liver, spleen, lungs and kidneys. Transmission of the parasite was also obtained by feeding young caimans with infected mosquitoes and it is suggested that both methods occur in nature. The finding of similar cysts containing cystozoites in the semi-aquatic lizard Neusticurus bicarinatus, experimentally fed with infected C. fatigans, suggests that other secondary hosts may be involved

Normal Quantity and Distribution of Mast Cells and Eosinophils in the Pediatric Colon

The normal number and distribution of mast cells (MCs) and eosinophils in colonic mucosa are largely unknown. Accordingly, we examined colonic biopsies obtained during endoscopic examinations of pediatric patients. The study included 41 patients (21 males and 20 females). The mean age was 11.72 years (range 3.3-19.7 years). Patients were followed for a mean time of 23.4 months (range 12-50 months). Our results showed a gradual decrease in the number of eosinophils in the lamina propria from the cecum to the descending colon (14.2 ± 6.1 and 10.7 ± 5.6 eosinophils//high-power field [hpf], respectively), with another peak in the rectosigmoid (12.4 ± 6.1 eosinophils/hpf). Eosinophils within the surface and crypt epithelium were more commonly encountered in the cecum and the rectosigmoid. Eosinophils clusters were rare but were more frequently found in the cecum and rectosigmoid. The largest number of MCs was observed in the descending colon and the lowest in the rectosigmoid (17.56 ± 7.28 and 14.5 ± 6.35 MCs/hpf, respectively). No MCs were identified within the surface epithelium. Very rare MCs were observed within the crypt epithelium, with the highest number observed in the cecum (0.34 ± 0.53 MCs/hpf) and the lowest number observed in the descending colon (0.02 ± 0.16 MCs/hpf). More MCs were present in the cecum and descending colon of females vs males (P  =  0.02 and 0.04, respectively). Our results establish baseline gastrointestinal eosinophils and MC counts in various parts of the pediatric colon

Eosinophilic Colitis

Abstract Eosinophilic gastrointestinal disorders (EGID) form a heterogeneous group of diseases, which are classified according to the site of involvement and to the depth of infiltration of the different layers of the gut. The prevalence of these diseases decreases toward the distal part of the gastrointestinal tract. Since it was first described on pathological specimens by Kaijser in 1937, approximately 300 cases of eosinophilic gastroenteritis have been published. The diagnosis of primary EGID is based on the presence of gastrointestinal symptoms; on histology showing eosinophilic infiltration, usually with eosinophils in an intraepithelial position; and on the exclusion of secondary causes of eosinophilia such as drugs, malignancy, or inflammatory bowel disease. Peripheral eosinophilia is not necessary for the diagnosis

Eosinophilic colitis: epidemiology, clinical features, and current management

Primary eosinophilic gastrointestinal disorders (EGIDs) represent a spectrum of inflammatory gastrointestinal disorders in which eosinophils infiltrate the gut in the absence of known causes for such tissue eosinophilia. EGIDs can be subgrouped as eosinophilic esophagitis (EE), eosinophilic gastroenteritis (EG), and eosinophilic colitis (EC). The least frequent manifestation of EGIDs is EC. EC is a heterogeneous entity with a bimodal age distribution, presenting with either an acute self-limited bloody diarrhea in otherwise healthy infants or as a more chronic relapsing colitis in young adults. The pathophysiology of primary EC appears related to altered hypersensitivity, principally as a food allergy in infants and T lymphocyte-mediated (i.e. non-IgE associated) in young adults. In adults, symptoms include diarrhea, abdominal pain, and weight loss. Endoscopic changes are generally modest, featuring edema and patchy granularity. Although standardized criteria are not yet established, the diagnosis of EC depends on histopathology that identifies an excess of eosinophils. Therapeutic approaches are based on case reports and small case series, as prospective randomized controlled trials are lacking. Eosinophilic colitis in infants is a rather benign, frequently food-related entity and dietary elimination of the aggressor often resolves the disorder within days. Adolescent or older patients require more aggressive medical management including: glucocorticoids, anti-histamines, leukotriene receptors antagonists as well as novel approaches employing biologics that target interleukin-5 (IL-5) and IgE. This review article summarizes the current knowledge of EC, its epidemiology, clinical manifestations, diagnosis, and treatment