Initial characterization of an autoclaved Toxoplasma vaccine in mice.

Toxoplasmosis is a zoonotic protozoal disease that has a major significance from the perspectives of public health and veterinary medicine. Therefore, an obvious long-term goal of many scientists would be the development of an effective vaccine. In this study, autoclaved vaccine was evaluated for its ability to protect mice against Toxoplasma gondii RH challenge as an acute infection model. Results showed that autoclaved Toxoplasma vaccine (ATV) when combined with BCG as an adjuvant was effective in triggering cell mediated immunity as shown by a significant increase in the percentage of splenic CD8+ T-lymphocytes. Following challenge, death of mice vaccinated with ATV was delayed for nine days. There was a significant decrease in parasite density in different organs, and a marked reduction of pathological changes in the liver suggesting that significant immune responses were mounted following vaccination. Future studies are warranted to test the vaccine against challenge with brain cysts as a chronic infection model and to evaluate it with other recent immunization strategies that can further enhance its immunogenicity.

A study on Blastocystis hominis in food-handlers: diagnosis and potential pathogenicity.

Proper diagnosis of Blastocystis hominis in not performed routinely in medical laboratories of developing countries; consequently clinical significance of this common intestinal protozoon is liable to remain unsettled. Food-handlers are more prone to get and transmit this feco-oral infection. This work compared the sensitivity of direct diagnostic methods to detect B. hominis in stool, estimate the true prevalence among food-handlers in Sirte-Libya, to clarify the association between the parasite and gastrointestinal symptoms and the response to specific treatment. A total of 400 male food-handlers aged 18-50 year were included. Each was subjected to clinical questionnaire and 3 stool examinations by different methods. The results showed high prevalence of B. hominis in food-handlers (35.5%). Short- term in vitro culture (on Boeck and Derbholav's medium) was the most sensitive method for detection of B. hominis (35.5%), followed by permanent Trichrome-stained smear (27.5%); saline-sedimentation concentrated smear (21%) and direct iodine smear (14%). Of 108 cases having B. hominis alone, 68.5% were symptomatic. Diarrhea was the most frequent symptom (75.6%), followed by abdominal pain (66.2%) and flatulence (43.2%). Fecal parasite-load was significantly higher in symptomatic cases than asymptomatic; parasite and symptoms disappeared after metronidazole treatment. So, culture should be used on routine basis to detect B. hominis which should be considered pathogenic particularly when present alone in large numbers in symptomatic patients.

Anthelmintic effect of artesunate in experimental heterophyid infection.

Artesunate is a water-soluble semi-synthetic drug derived from artemisinin which is extracted from leaves of the Chinese plant Artemisia annua. This successful basically-antimalarial drug has been proved to be also effective against trematodes like Schistosoma japonicum, S. mansoni, Fasciola hepatica and Clonorchis sinensis. The present work aimed to investigate the in-vivo efficacy of artesunate against heterophyids in mice, using praziquantel as a therapeutic control. Results showed that artesunate was effective in treatment of experimental heterophyidiasis as proved by a 100% reduction of intestinal adult worm count at a dose regimen of 200 mg/kg/day, given for 3 successive days. Besides, surface tegumental damage of the adult worm was observed by SEM in form of bleb formation, disruption, erosion and peeling. The proved therapeutic efficacy of artesunate together with its reported safety, favor its possible use as a new alternative therapy in human heterophyidiasis.

Effect of mirazid (Commiphora molmol) on experimental giardiasis.

Mirazid -a purified oleo-resin extract derived from myrrh- with previously proved trematocidal activity, has been recently reported to be also effective against protozoa like Trichomonas vaginalis and cryptosporidium in humans. This experimental study aimed at investigating the possible therapeutic effect of mirazid on experimental Giardia lamblia infection in albino rats, using tinidazole as a therapeutic control. Results proved the efficacy of mirazid, as indicated by a 100% reduction in parasite- load of both intestinal and fecal parasitic counts, a direct toxic effect on Giardia trophozoite as revealed by SEM and TEM in form of cell membrane erosions together with increased cytoplasmic vaculation and dissociation, and also by reversal of the observed mucosal damage associated with Giardia after complete treatment. Starting trophozoite invasion of the mucosa was also demonstrated by TEM; its mechanism and possible pathogenic effect in giardiasis were discussed.

Disinfection efficacy of sodium dichloroisocyanurate (NADCC) against common food-borne intestinal protozoa.

The present study was conducted to investigate the efficacy of sodium dichloroisocyanurate (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.

Clinical and parasitological study on scabies in Sirte, Libya.

The present work aimed to determine the risk factors, clinical and parasitological skin lesion features and effective drug regimens. Study was carried out on 200 patients referred to dermatology outpatient clinics in Sirte-Libya. Each was subjected to detailed questionnaire, dermatological skin examination, parasitological skin scraping test (SST), burrow ink test (BIT), drug administration and follow up. Results revealed that females 59%, children 37.5% and military personnel 18% of immigrant families were particularly prone to scabies infestation. Effective risk factors included overcrowding, bed sharing, low hygienic and education levels. Commonest skin lesions included erythematous papules 93%, excoriated papules 77.5%, burrows 66%, pustulation 31%, vesicles 21.5 and nodules 3%. Predilection lesion sites were hand 86%, wrist 82%, abdomen 56%, male external genitalia 64.5% and female breast 28%. Specific SST was positive in 67.3% of cases, particularly sensitive in early cases with short itching duration. BIT was positive in 62%. Topical permethrin proved more effective than precipitated sulpher with cure rates of of 100% and 85.3% in 21% and 75% of cases, respectively. Ivermectin was 100% effective in 4% of cases.

Emerging cutaneous leishmaniasis in Sirte-Libya: epidemiology, recognition and management.

The present work aimed to determine the risk factors, lesion pattern and effective therapy of emerging ZCL in Sirte-Libya. The study was carried out on 163 patients referred to health centers of Al-Gadaheya and Al-Hisha villages in the years 2006 & 2007. Methods consisted of a predesigned questionnaire (personal and demographic data), clinical examination of lesions, and parasitological examination by slit smear, treatment and follow up. Results showed an annual incidence of 0.95%, with onset peak during autumn months. Important local risk factors included: increased occupational exposure of farmers and construction worker to infection from fat sand rat burrows, facilitated by lack of prevention knowledge and prophylactic measures; close association of bad-ventilated animal shelters to houses, and increased soil moisture by warm spring ponds. The majority of lesions were multiple (73%) located on legs, arms, and face 66.8%, 52.1% and 41.1%. Most lesions were active 1-2 month duration and 1-3 cm size, ulcerative type (77.3%), and papulo-nodular (21.5%). Giemsa slit smear proved quite reliable for active lesions, confirmed 79.5% of lesions. The majority of lesions (60.1%) were treated by intra-lesional Pentostam. Systemic route was restricted to facial, over-joint, multiple or large lesions producing, good response in 31.9%. Cryotherapy and oral Fluconazole gave satisfactory response in 5.5% & 2.5% of cases.

The adjuvant effects of IL-12 and BCG on autoclaved Leishmania major vaccine in experimental cutaneous leishmaniasis.

Cutaneous leishmaniasis is a universal disease causing skin ulceration and deformity. A reliable vaccine remains to be a possible practical means of control. The amastigotes multiply intracellulary in macrophages provoking a cell-mediated type of immune response. IL-12 is the central cytokine of CMI. It is produced by sensitized macrophages, stimulates both Th1 and NK cells to secrete IFN-gamma which in turn activates the intracellular killing of Leishmania in macrophages via increased oxygen radicals. This work aimed mainly at studying the adjuvant effect of IL-12 on autoclaved L. major (ALM) vaccine, compared to that of BCG in L. major infection. The material included five groups of Swiss albino mice; the test group infected after receiving ALM+IL-12, a non-infected control group, and three other control groups infected after receiving ALM+BCG, IL-12 alone and BCG alone L. major was cultured to provide promastigotes for vaccine and infection. The measured parameters included the lesion size, type and progress; the parasite density and the level of IFN-gamma in serum. The results showed that the best protection against challenge infection was obtained by ALM + IL-12 followed by ALM + BCG. The former is recommended for use as a vaccine with regards to its proved efficacy and known safety.

Study on human ophthalmomyiasis externa caused by Oestrus ovis larva, in Sirte-Libya: parasite features, clinical presentation and management.

Oestrus ovis larva is by far the commonest cause of human ophthalmomyiasis. The larva usually limits it's activity to the conjunctiva and cornea, but, penetration of the eye is a potential complication. Misdiagnosis is common and the condition of acute catarrhal conjunctivitis is ascribed to other causes. The study included 20 patients referred to university hospital of Sirte, Libya. Results showed that the condition was more common among adult male shepherds and farmers in rural areas. Important criteria for diagnosis were; sudden mobile foreign body sensation with abrupt itching and lacrimation occurring in endemic area, in warm months even without history of fly strike. Effective treatment consisted of mechanical removal of the larva by the cotton swap mounting technique which resulted in rapid improvement. Suffocation of residual larvae was mediated by use of liberal amounts of topical antibiotics. Slit lamp examination of larva showed that it was small, translucent, avoid the light beam and easily overlooked. Detailed microscopic examination of larval surface structures revealed a multi-component attachment apparatus consisting of oral hooks, inter-segmental spines, caudal spines and a multi-layered spiny thoracic complex described for the first time. These injurious structures are believed to be responsible through inflicting direct mechanical damage for the observed haemorrhage, ulceration or even the potential invasion, as these changes were more obvious in neglected cases. So, early diagnosis and treatment are essential to avoid complications.

Effect of Mirazid (Commiphora molmol) on experimental heterophyidiasis.

Mirazid (MZ), an oleo-resin extract derived from Myrrh was reported in several experimental and clinical trails to be safe and effective against other trematodes like schistosomiasis and fascioliasis. This experimental work aimed at investigating the possible efficacy of MZ against heterophyids (Pygidiopsis genata), using praziquantel as a therapeutic control. Results showed that MZ in emulsion form is a promising drug for the treatment of heterophyidiasis, as proved by significant reduction of worm count, overt surface tegumental changes like deformity and erosion of tegumental spines observed by scanning electron microscope (SEM). The effective dose regimen was 500 mg/kg/d for 3 successive days, produced 100% reduction in worm load. The proved efficacy of the drug, together with reported low toxicity, relative to praziquantel, favours its use as a natural new alternative therapy for the treatment of human heterophyidiasis.

The utility of lactoferrin in differentiating parasitic from bacterial infections.

Lactoferrin is an iron binding glycoprotein found in the 2ry granules of PMN. In order to determine the usefulness of such marker for neutrophilic activity in differentiating cases suffering from amoebic and bacillary dysentery, Schistosoma and bacterial UTI infections, we examined stool and urine specimens using anti-lactoferrin antibodies (lactoferrin latex agglutination test: LFLA), compared with different standard gold techniques. Our results demonstrated that cases with either shigllosis or UTI revealed a high lactoferrin titer which was positively correllated with the number of PMN. In addition cases with Entamoeba histolytica or S. haematobium were characterized by relatively lower inflammatory process as expressed by mild lactoferrin titer which was also correlated with the PMN count. In addition, the findings of the present work indicated that LFLA was sensitive and specific when used alone and its sensitivity was augmented after coupling with other simple indirect methods of diagnosis. In conclusion, results described the reliability of using LFLA as a simple, rapid, sensitive method in differentiating, certain parasitic from bacterial diseases.