Development of human and mouse strain of Hymenolepis nana in mice

Gene-based molecular characterization of cox1 and pnad5 in Hymenolepis nana isolated from naturally infected mice and rats in Saudi Arabia

Mice and rats are animals commonly used in research and laboratory testing. Compared with other animal species, they harbor many more zoonotic agents. Hymenolepis nana (H. nana) is a common tapeworm that parasitizes both humans and rodents. Although this tapeworm is of socio-economic importance worldwide, information related to its mitochondrial genome is limited. The present study examined the sequence diversity of two mitochondrial (mt) genes, subunit I of cytochrome oxidase (cox1) and NADH dehydrogenase subunit 5 (pnad5), of H. nana in mice and rats from two geographical regions of Saudi Arabia (Makkah and Riyadh). Partial sequences of cox1 and pnad 5 from individual H. nana isolates were separately amplified using polymerase chain reaction (PCR) and sequenced. The GC contents of the sequences ranged between 31.6–33.5% and 27.2–28.6% for cox1 and pnad5, respectively. The genomic similarity among specimens determined via cox1 primer and pnad5 primer was 97.1% and 99.7%, respectively. Based on these primers, our data did not indicate any differences between H. nana from rat and mice isolates. Results demonstrated that the present species are deeply embedded in the genus Hymenolepis with close relationship to other Hymenolepis species, including H. nana as a putative sister taxon, and that the isolates cannot be categorized as belonging to two different groups with origins in Makkah and Riyadh.

Experimental infection and adaptation ofRodentolepis nanato the Mongolian jirdMeriones unguiculatus

A mouse-derived strain ofRodentolepis( = Hymenolepis)nanawas transferred to the Mongolian jirdMeriones unguiculatus. It was found thatM. unguiculatushas low susceptibility toR. nanamouse isolates. Likewise, adaptation of the parasite to jird hosts, in the absence of dexamethasone treatment, was not demonstrable, at least during ten-passage trials. Nevertheless, the parasite was able to establish, grow and develop to gravid adults inM. unguiculatustreated daily with dexamethasone. Prepatent periods in dexamethasone-treated jirds in ten-passage series ranged from 10 to 17 days post-infection (DPI), the average being 12 days, and the patent periods lasted from 18 to 30 DPI, with an average of 25 days. The population pattern of faecal egg output in immunosuppressed jirds suggests that under a daily dexamethasone treatment protocol, the parasite is able to maintain egg production as long as treatment is sustained.

Resistance of mice to infection with the human strain of Hymenolepis nana

Six attempts were made to infect mice by feeding them eggs of the human strain of Hymenolepis nana, but none was successful. No eggs were found in the mouse faeces 14 days after feeding, and no adult worms were recovered at post mortem examination. In attempts to induce cysticercoids to infect mice, beetles were either fed on infected human faeces or given Hymenolepis eggs on filter paper. Both methods were unsuccessful, as no cysticercoids were recovered six days after exposure of the beetles.

Kinetics of mast cells, eosinophils and phospholipase B activity in the spontaneous-cure response of two strains of mice (rapid and slow responder) to the cestode Hymenolepis nana

Primary egg-derived infection of Hymenolepis nana (100 eggs) in BALB/c (rapid responder) and C3H (slow responder) mice resulted in increased levels of mucosal mast cells (MMCs), eosinophilia (bone marrow, peripheral, tissue) and phospholipase B activity. The response appeared to be similar in both strains used, with a slight difference in cellular accumulation but a significantly earlier response in BALB/c than in C3H mice. These findings suggest that the prolongation of H. nana infection in C3H mice may be related to the delayed appearance of MMCs and eosinophils, which triggers a slower generation of the intestinal inflammation response. The rapidity with which phospholipase B activity increased was strictly correlated with eosinophil tissue number; this further supports the hypothesis for a direct parallel between eosinophils and phospholipase B activity in infected tissue.

Hydatidosis in Sardinia: review and recommendations

In Sardinia, hydatidosis due to Echinococcus granulosus is endemic and constitutes a current and important problem in the economy and public health. This paper reviews the epidemiological aspects, including the geographical distribution, and the socio-cultural factors involved in the dissemination of hydatidosis. Hospital data indicate that about 200 people undergo surgery for hydatid cysts every year with an average of 8.8 deaths annually. An average of 80% of the sheep are infected, constituting a livestock loss estimated as over 20 billion liras per year. The benefits expected from a hypothetical control programme amount to approximately 32 billion liras against an investment of 17 billion liras in a control programme extending over a period of 10 years. The eradication campaign should result in a gradual reduction of infection rate from 80% to 10% in sheep, from 30% to 3-5% in dogs and in a reduction of human morbidity from 200 to 15 cases, equal to a prevalence rate of 1 per 100,000 inhabitants.