Molecular Diagnosis of a Hybridized Tapeworm (Between Taenia Saginata and Taenia Asiatica) Infection Case in Yunnan, China, 2019

Human taeniasis is still prevalent in many countries in the world and affecting human health. Three species of tapeworms in the genus Taenia, including Taenia asiatica, Taenia saginata, and Taenia solium are the most common pathogens for the diseases. The genetic relationships of T. saginata and T. asiatica are close. The natural hybridization between these two has not been clinically diagnosed in China. In this study, we report an 18-year-old male patient with taeniasis hospitalized in Yunnan, China, in 2019. The patient was treated with traditional Chinese medicine, and a tapeworm around 2.7 m long was expelled. The morphology of egg and gravid proglottid of the tapeworm were revealed. More interesting is that the tapeworm was identified as a T. saginata-T. asiatica hybridized by the molecularly and phylogenetic analysis. The case study reported the first human taeniasis caused by the T. saginata and T. asiatica hybridization and suggested that the new types of hybridized taeniases exist in China and further investigation and research on the pathogens in Yunnan is needed.

Interactions between the intestinal cestode Polyonchobothrium clarias (Pseudophyllidea: Ptychobothriidae) from the African sharptooth catfish Clarias gariepinus and heavy metal pollutants in an aquatic environment in Egypt

In an aquatic environment, there is a profound and inverse relationship between environmental quality and disease status of fish. Parasites are one of the most serious limiting factors in aquaculture. Therefore, the present investigation was carried out during the period of February–December 2014 to determine the parasitic infections in the African sharptooth catfish Clarias gariepinus, relative to the capability of internal parasites to accumulate heavy metals. Up to 100 catfish were examined for gastrointestinal helminths and 38% of fish were found to be infected with the cestode Polyonchobothrium clarias. The morphology of this parasite species, based on light and scanning electron microscopy, revealed that the adult worm was characterized by a rectangular scolex measuring 0.43–0.58 (0.49 ± 0.1) mm long and 0.15–0.21 (0.19 ± 0.1) mm wide, with a flat to slightly raised rostellum armed with a crown with two semicircles each bearing 13–15 hooks, followed by immature, mature and gravid proglottids which were about 29–55 (45), 16–30 (24) and 15–39 (28) in number, respectively. The mature proglottid contained a single set of genitalia in which medullary testes measured 0.09–0.13 (0.11 ± 0.01) mm long and 0.05–0.08 (0.06 ± 0.01) mm wide; a bi-lobed ovary was situated near the posterior margin of the proglottid, extending laterally up to the longitudinal excretory canals; the tubular uterus arose from the ootype up to the anterior margin of the proglottid; and vitelline follicles were cortical. The greater portion of the gravid proglottid was occupied by a uterus filled with unoperculate and embryonated eggs. Chemical analysis confirmed that the concentrations of heavy metals (Zn, Cu, Mn, Cd, Ni and Pb) accumulated in P. clarias were higher than in fish tissues and values recommended by FAO/WHO, with the exception of Zn, which was found to be higher in fish kidneys than in the cestode. This supports the hypothesis that cestodes of fish can be regarded as useful bioindicators when evaluating the environmental pollution of aquatic ecosystems by heavy metals.

Experimental infection of dogs with Echinococcus granulosus (Batsch, 1986) from protoscoleces of donkey's hydatid cyst

This study was conducted, for the 1st time in Iraq, to infect 5 puppies, 1 - 5 month old, with protoscoleces of hydatid cyst isolated from the liver of donkey, slaughtered at zoo abattoir of Al-Zawra park in Baghdad, at a dose rate of 10000 protoscoieces i puppy (n=2) and 20000 protoscoleces / puppy (n=3) for 35 and 40 days post infection. The dogs were killed and the developed Echinococcus granulosus were isolated from the small intestine. Results of the study revealed variation in the period of maturation of the collected cestodes, and the mean total length of the mature worms at 35 days PI was 4.53+ 0.24 mm, and for those at 40 days PI was 7+ 0.20 mm, whereas for the gravid ones at the same age of the latter was 8.57 + 0.25 mm. Results found that infection rate with E. granulosus, which their strobilae composed from 4 proglottids at 35 days PI, was 29.03%, and with those, which their strobilae composed from 5 proglottids at 40 days PI, the rate was 0.76%. It was found that the mean length of the gravid proglottid equal to or longer than half the total worm length with a ratio of 1.77 + 0.05 for those at 35 days of age, and 2.2 + 0.35 and 1.93 + 0.01 for mature and gravid cestodes at the age of 40 days.

Effects of 5-hydroxytryptamine and histamine on establishment, production, and reproduction by Hymenolepis diminuta in the final and intermediate hosts

The effects of chronic administration of 5-hydroxytryptamine (serotonin, 5-HT) and histamine for 15 days, commencing 24 h after infection, on establishment, production, and reproduction by the tapeworm Hymenolepis diminuta in the rat intestine have been studied. Chronic treatment with 5-HT at the rate of 10 or 20 mg/rat per 24 h neither affected parasite production (growth) nor caused a significant rejection of the infection by the rat host. The number of eggs shed by the parasite and the number of eggs per gravid proglottid were reduced over the final 24-h period prior to sacrifice of the hosts.Similar treatment with histamine at the higher dose rate resulted in a significant reduction in the size of the infection and a significant increase in average worm weight. The number of eggs per gram of faeces and per proglottid was significantly reduced, as was also the number of cysticercoids that developed in beetles (Tribolium confusum) that had been fed on the gravid proglottids from histamine-treated worms. Results at the lower dose rate were similar, although the changes were smaller. The histamine treatment may have induced an immunological response by the host to the infection similar to that previously reported for this particular host–parasite system at higher levels of infection or in challenge infections.

Studies on the Functional morphology of the Scolex and of the Genitalia in Echinobothrium brachysoma Pintner and E. affine Diesing from Raja clavata L.

1. Echinobothrium brachysoma Pintner and E. affine Diesing have been found in the spiral valve of Raja clavata L. off the coast of Britain.2. The spiral valve is lined by tubular crypts into which the scolices of the worms are thrust, the strobila, with one gravid proglottid, being free in the lumen.3. The functional morphology of the scolex of E. brachysoma has been described. That of E. affine appears to be similar.4. The scolex adheres, mainly, by the apical hooks which can be raised by inner and outer elevator muscles attached to their roots and closely associated with the rostellum.5. The rostellum can be protruded by the contraction of a dorsal and a ventral protractor muscle. Movements of the rostellum elongate the scolex in a dorsoventral direction, forcing the apical hooks against the crypt wall and supporting them.6. The peduncle hooks are not often embedded in the epithelium. Both series of hooks damage the epithelial lining of the crypt.7. The remaining musculature, excretory and nervous systems are described.8. The genitalia are essentially the same in both species. The number of testes varies from one proglottid to another in the same worm. In E. brachysoma the mid-ventral genital atrium is near the posterior end which affects the course of the vagina. The eggs in both species include two yolk cells which are similar to those of the Digenea and Pseudophyllidea.