M. Hilali

Isolation and molecular characterization of Toxoplasma gondii from chickens and ducks from Egypt.

The prevalence of Toxoplasma gondii in free range chickens is a good indicator of the prevalence of T. gondii oocysts in the environment because chickens feed from the ground. In the present study, prevalence of T. gondii in 121 free range chickens (Gallus domesticus) and 19 ducks (Anas sp.) from a rural area surrounding Giza, Egypt was assessed. Blood, heart, and brain from each animal were examined for T. gondii infection. Antibodies to T. gondii, assayed with the modified agglutination test (MAT), were found in 49 (40.4%) chickens in titers of 1:5 in 11, 1:10 in four, 1:20 in four, 1:40 in eight, 1:80 in 10, and 1:160 or more in 12 chickens. Antibodies were found in three ducks each with a titer of 1:80. Hearts and brains of seropositive (MAT > or = 1:5) chickens and ducks were bioassayed in mice. Additionally, hearts and brains of seronegative (MAT<1:5) animals were bioassayed in T. gondii-free cats. T. gondii was isolated from 19 of 49 seropositive chickens (one with a titer of 1:5, two with a titer of 1:20, one with a titer of 1:40, five with a titer of 1:80, three with a titer of 1:160, and seven with a titer of > or = 1:360). One cat fed tissues pooled from 15 seronegative chickens shed T. gondii oocysts, while two cats fed tissues of 34 seronegative chickens did not shed oocysts. T. gondii was isolated from one of the seropositive ducks by bioassay in mice. The two cats fed tissues from 16 seronegative ducks did not shed oocysts. Genotyping of 20 chicken isolates of T. gondii using the SAG 2 locus indicated that 17 isolates were type III and three were type II. The duck isolate of T. gondii was type III. The mice inoculated with tissue stages of all 21 isolates of T. gondii from chickens and ducks remained asymptomatic, indicating that phenotypically they were not type I because type I strains are lethal for mice. Infections with mixed genotypes were not found.

Seroprevalence of antibodies to Neospora caniuum and Toxoplasma gondii in water buffaloes (Bubalus bubalis) from Egypt

Sera from 75 water buffaloes from Egypt were examined using a direct agglutination test incorporating mercaptoethanol for antibodies to Neospora caninum and Toxoplasma gondii. Antibodies to N. caninum were found in 51 (68%) of 75 buffaloes in titres of 1:20 (six buffaloes), 1:40 (15 buffaloes), 1:160 (one buffalo), 1:320 (one buffalo) and > or = 1:640 (28 buffaloes), using N. caninum formalin-preserved whole tachyzoites as antigen. Antibodies to T. gondii were not found in a 1:100 dilution of serum of any of the 75 buffaloes, using T. gondii as antigen, indicating specificity in the detection of antibodies to N. caninum. This is the first report of N. caninum prevalence in water buffaloes, which are economically very important domestic animals in developing countries.

Prevalence of Neospora caninum and Toxoplasma gondii antibodies in sera from camels from Egypt.

Sera from camels from Egypt were examined by the direct agglutination tests incorporating mercaptoethanol for antibodies to Neospora caninum and Toxoplasma gondii. Antibodies to N. caninum were found in 6 of 161 camels in titers of 1:40 (2 camels) and 1:80, 1:160, 1:640, and 1:1280 in 1 camel each, using N. caninum formalin preserved whole tachyzoites as antigen. Antibodies to T. gondii were found in 17.4% of 166 camels in titers of 1:25 (3 camels), 1:50 (18 camels). and > 1:500 (8 camels) using T. gondii tachyzoites. All 6 camels with N. caninum antibodies had no T. gondii antibodies in 1:4 dilution of serum, indicating specificity of the reaction. This is the first report of N. caninum prevalence in Egypt.

Genetic characterization of viable Toxoplasma gondii isolates from stray dogs from Giza, Egypt.

Stray dogs are considered as sentinels in the epidemiology of Toxoplasma gondii because they are carnivores and eat variety of foods, including garbage. In the present study, tissues and sera of 51 stray dogs (Canis familiaris) from Giza, Egypt were examined for T. gondii infection. Sera were examined for antibodies to T. gondii by the modified agglutination test (MAT); 50 of 51 (98%) were seropositive with titers of 20 in four, 40 in four, 80 in one, 100 in eight, 200 in 17, 400 in 11, 800 or higher in five. Hearts of 43 seropositive dogs were bioassayed in mice. Viable T. gondii was isolated from 22 dogs; these isolates were designated TgDogEg1 to TgDogEg22. DNA isolated from cell culture derived tachyzoites of 22 isolates was genotyped using 10 PCR-restriction fragment length polymorphism markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico). The results revealed three genotypes and one mixed infection. The three genotypes are ToxoDB PCR-RFLP #2 (type III, four isolates), #3 (type II variant, 11 isolates), #20 (six isolates), 1 mixed infection. These results revealed the dominance of clonal type II, III and ToxoDB #20 lineages of T. gondii in stray dogs from Giza, Egypt.

Camel (Camelus dromedarius) and sheep (Ovis aries) meat as a source of dog infection with some coccidian parasites

Experimental infection of dogs with camel (Camelus dromedarius) meat resulted in infection of the dogs with Isospora canis, Hammondia heydorni and Sarcocystis cameli. The dogs fed sheep (Ovis aries) meat passed oocysts of Isospora canis, Isospora ohioensis and sporocyts of Sarcocystis spp. Extraintestinal stages were detected in the intestinal lymph node of a rabbit killed 4 days following inoculation with Isospora ohioensis oocysts. Dogs fed the rabbit (killed 4 days after inoculation with I. ohioensis) passed I. ohioensis oocysts in their faeces 8 days post-infection.

OBSERVATIONS ON THE USE OF ELISA FOR DETECTION OF BABESIA BIGEMINA SPECIFIC ANTIBODIES

An indirect enzyme-linked immunosorbent assay (ELISA) was evaluated to study the cause of the high level of background reactions which hinders the application of ELISA as a field diagnostic test for Babesia bigemina. Different blockers to improve the specificity of the ELISA were compared. THe use of soya milk (25%), gelatin (2.5%) and chicken serum (2%) did not significantly improve the specificity of the test. It was noted that the presence of fibrinogen contributed to the positive ELISA results more than the presence of B. bigemina specific antigen. This conclusion was confirmed by testing bovine fibrinogen as a host protein antigen in ELISA which strongly responded against B. bigemina positive control sera. It is suggested that application of ELISA for B. bigemina is still unreliable until a more purified Babesia-specific antigen or specific monoclonal antibodies are available.

Haematological and biochemical changes in buffalo calves inoculated with Sarcocystis fusiformis from cats

Two groups of buffalo calves were infected with Sarcocystis fusiformis sporocysts. Animals of the first group received each 5 X 10(5) sporocysts, those of the second group 5 million sporocysts. All calves were clinically normal during 6 weeks after infection. Minor changes were observed in the blood cytology, serum alkaline phosphatase, glutamic oxalacetic transaminase, glutamic pyruvic transaminase, total proteins, urea and glucose of infected buffalo calves.

Incidence and monthly prevalence of GLasterophilus spp. larvae (Diptera: Gasterophilidae) in the stomuch of donkey (Equus asinus) in Egypt

The stomachs of 118 donkeys were examined at postmortem during the period from March 1982 to February 1983 for Gasterophilus spp. larvae. G. intestinalis larvae clustered in groups near the boundary of the glandular and non-glandular epithelium of the stomach and infested 98.3% of the donkeys with highest numbers in July and lowest numbers in October. G. nasalis larvae were mainly attached near the pylorus and first part of the duodenum and infested 87.3% of donkeys with highest incidence in December and lowest in October. The ratio of the second and third instars of G. intestinalis to G. nasalis ranged from 71% to 29%. The percentage of donkeys infested with 1-100, 101-200 and 201-300 larvae was 72.0, 18.6 and 4.3% for G. intestinalis and 76.3, 8.5 and 0.8% for G. nasalis.

Ultrastructure of Besnoitia cysts from reindeer (Rangifer tarandus tarandus L)

The ultrastructure pf Besnoitia cysts in reindeer is described. The observations made on Besnoitia cysts and merozoites indicate a form distinct enough to be placed in a new species - Besnoitia tarandi.

Serological Survey of Dogs From Egypt for Antibodies to Leishmania Species

Abstract:  Leishmaniasis is an insect-transmitted parasitic disease with a worldwide distribution. Leishmania spp. infections cause a broad spectrum of clinical signs, ranging from skin lesions to fatal visceral disease. Dogs are a major reservoir host for visceral leishmaniasis in humans. While the disease is endemic in the Middle East and North Africa, little is known concerning canine Leishmania spp. infections in Egypt. Accordingly, blood samples were collected from 50 stray dogs in Giza, Egypt. Canine sera were tested for antibodies to visceralizing Leishmania spp. by commercial immunochromatographic strip assays based on recombinant antigen K39. Antibodies to Leishmania spp. were found in 5 of 50 (10%) of dogs tested from Egypt. Results from this study indicate that stray dogs are exposed to visceralizing Leishmania species in Egypt.