Disinfection efficacy of sodium dichloroisocyanurate [NaDCC] against common food-borne intestinal protozoa

The present study was conducted to investigate the efficacy of sodium dich-loroisocyanurate [NaDCC] on the infective stages of common food-borne intestinal protozoa; Entamoeba histolytica [E. histolytica], Giardia lamblia [G. lamblia], Cryptosporidium, Cyclospora and Microsporidia; beside its effect on raw green vegetables and fruits. Parasites, isolated from stool of patients with diarrhea or dysentery, were exposed to NaDCC solution [1g/l] for one and two hours. Disinfection effect of NaDCC was assessed by in-vitro viability, using trypan blue stain, and infectivity bioassay in laboratory animals as indicated by fecal and intestinal parasitic counts. Raw vegetables and fruits were dipped in NaDCC solution in the same concentration and exposure time as used for treatment of the parasites. Results revealed statistically significant reductions in viability and infectivity of all examined parasites indicating their susceptibility to NaDCC. Relative variations in susceptibility were revealed; E. histolytica and G. lamblia were most susceptible [100% reduction] followed by Microsporidia then Cryptospridium and Cyclospora. NaDCC did not affect the consistency, color, taste or flavor of raw green vegetables and fruits. The proved efficacy of NaDCC, in cheap and convenient dry tablet form, makes it a promising tool in decontaminating raw vegetables and fruits from food-borne protozoan parasites at household and restaurant levels as well as in catering and fresh produce industry. It is also recommended for disinfection of food preparation surfaces and equipment

utility of direct agglutination [DAT] and fast agglutination screening [FAST] tests in serodiagnosis of experimental microsporidiosis

The present study was designed to evaluate the efficiency of two serodiagnostic tests; the direct agglutination test [DAT] and the fast agglutination screening test [FAST] in the diagnosis of Microsporidia in experimentally infected mice and to differentiate between different species of the parasite. The swiss albino mice were divided into non infected control and infected experimental groups which were further subdivided into ten subgroups. Ten samples of microsporidial spores were isolated from ten human stools and each one was used to infect each subgroup of mice. Stool and sera were collected weekly from each subgroup from the 1[st] to the 4[th] week post infection [PI]. DAT and FAST tests, using antigen prepared from the different species of microsporidial spores were used to detect antibodies in sera of different mice subgroups. The cross reactivity of microsporidial spores with the antibodies of Cyclospora cyatenensis and Cryptosporidium parvum was investigated by DAT and FAST. The results proved that DAT and FAST were effective in detecting microsporidial antibodies in sera of experimentally infected mice from the 2[nd] week PI till the end of the study, without cross reactivity with C. cyatenensis or C. parvum. They failed to differentiate between different Microspoiridia species used but, they gave good interpretation and they were specific and sensitive, and did not need sophisticated equipments

Immunization against trichinellosis using microwaved larvae of trichinela spiralis

The present study evaluated the effect of microwave irradiation on infective larvae of Trichinella spiralis [T. spiralis] by the ultrastructure changes of the microwaved larvae [ML] using scanning electron microscope [SEM]. The ML tested the ability to immunize mice against a challenge infection with T. spiralis. For the optimal dose and the best route of immunization inducing protection against challenge infection, two doses were used; 300 and 600 ML as one or two-dose regimen, each dose was given orally and intraperitoneally [IP]. SEM revealed tegumenttal damage of the ML in the form of distortion, loss of normal fold pattern and depressions or papillae protruded from their outer surface. After administration of the ML [orally or IP] to the non-infected control mice, neither adults nor larvae were detected in the intestines or muscles respectively. This indicated loss of larvae infectivity after exposure to the microwave irradiation. Also, a significant protection against challenge infection with T. spiralis was demonstrated in experimental mice immunized by ML, orally or IP. This was assessed by a statistically significant decrease in adult and muscle larval count, compared with the non-immunized infected control. Complete protection against both adults and larvae [100%] was achieved by IP injection of two doses of 600 ML, two weeks apart. The results suggested the feasible application of the microwave irradiation on meat for its decontamination from T. spiralis larvae. Such a method might be a promising a prophylaxis vaccine against trichinellosis in animals and/or humans