Regulation of intestinal epithelial cell cytoskeletal remodeling by cellular immunity following gut infection.

Gut infections often lead to epithelial cell damage followed by a healing response. We examined changes in the epithelial cell cytoskeleton and the involvement of host adaptive immunity in these events using an in vivo model of parasitic infection. We found that both ezrin and villin, key components of the actin cytoskeleton comprising the brush border (BB) of intestinal epithelial cells (IECs), underwent significant post-translational changes following gut infection and during the recovery phase of gut infection. Intriguingly, using mice lacking either CD4(+) or CD8(+) T-cell responses, we demonstrated that the mechanisms by which ezrin and villin are regulated in response to infection are different. Both ezrin and villin undergo proteolysis during the recovery phase of infection. Cleavage of ezrin requires CD4(+) but not CD8(+) T cells, whereas cleavage of villin requires both CD4(+) and CD8(+) T-cell responses. Both proteins were also regulated by phosphorylation; reduced levels of phosphorylated ezrin and increased levels of villin phosphorylation were observed at the peak of infection and correlated with reduced BB enzyme activity. Finally, we show that infection also leads to enhanced proliferation of IECs in this model. Cytoskeletal remodeling in IECs can have critical roles in the immunopathology and healing responses observed during many infectious and non-infectious intestinal conditions. These data indicate that cellular immune responses can be significant drivers of these processes.

Tetrameres (Tetrameres) grusi (Shumakovich, 1946) (Nematoda: Tetrameridae) in Eurasian cranes (Grus grus) in central Iran.

The proventriculi of 11 Eurasian cranes (Grus grus) from central Iran were examined for the existence of parasitic helminths. Preliminary reports suggested that the death of these birds was related to untimely cold weather. Nine proventriculi (82%) were heavily infected by the nematode Tetrameres grusi. Glandular structure of the infected proventriculi was replaced by epithelial atrophy but significant inflammatory reactions were not observed in any of the infected organs. In serious infections, the nematode produced vast structural and functional changes, causing organ dysfunction and glandular necrosis. The coincidence of heavy helminth infection at times of environmental stress may lead to debilitation, wasting, and perhaps mortality in migratory cranes.

Zoonotic implications of the swine-transmitted protozoal infections.

Pig production is an important part of the economy in many countries. Domestic and wild pigs (Sus scrofa) are susceptible to a wide range of infectious and parasitic diseases. Some of these diseases are specifically limited to pigs while some of the other diseases are shared with other species of wildlife and domestic livestock. As the numbers and geographic distribution of wild and domestic swines continue to increase, it is certain that the number of contacts between these swines and domestic livestock will also increase, as will the probability of human exposure to the parasites of swine directly or indirectly. Here, we will discuss the protozoal infections of pigs, which have the potential to infect humans and provide reasonable risk assessment for zoonotic transmission.

The distribution of Entamoeba histolytica and Entamoeba dispar in northern, central, and southern Iran.

The present study was carried out from August 1999 through February 2002 in order to determine the prevalence of Entamoeba histolytica and Entamoeba dispar in three different climatic regions of Iran by using a PCR-RFLP method. A total of 16,592 stool samples were randomly collected from different age-groups in central, northern, and southern Iran in both urban and rural areas. The samples were examined by direct and formalin-ether concentration methods. A total of 226 samples were positive for E. histolytica/E. dispar cysts. Of these, 101 isolates were cultured and maintained successfully in Robinson's medium and were identified by the PCR-RFLP method. The study showed that 92.1% of isolates were E. dispar and 7.9% were E. histolytica or mixed infections. The ratio of E. histolytica to E. dispar was higher in southern regions (tropical and subtropical) than in the other two regions. This study demonstrated that E. dispar is the predominant species found among "cyst passers" in Iran.

Intestinal protozoa in wild boars (Sus scrofa) in western Iran.

A total of 12 gastrointestinal tracts of wild boars (Sus scrofa) from western Iran (Luristan) were examined for protozoan infection between September 2000 and November 2001. Of 12 boars examined, 67% harbored one or more species of the following protozoa: Balantidium coli (25%), Tritrichomonas suis (25%), Blastocystis sp. (25%), Entamoeba polecki (17%), Entamoeba suis (8%), Iodamoeba butschlii (17%), and Chilomastix mesnili (8%). Four of these protozoan species also are reported in humans, and persons living in rural areas where wild boars are abundant should take precaution to avoid infection.

Helminth parasites of the wild boar, Sus scrofa, in Luristan province, western Iran and their public health significance.

Seven helminth species were obtained from 12 wild boars (Sus scrofa) during a survey from 2000 to 2001 in Luristan province, western Iran. These species include the cestode larvae Cysticercus tenuicollis (25%), C. cellulosae (8.3%), the nematodes Metastrongylus apri (41.6%), M. pudendotectus (16.6%), M. salmi (8.3%), Trichuris suis (8.3%) and the acanthocephalan Macracanthorhynchus hirudinaceus (41.6%). No trematodes were found. Seven wild boars (58.3%) were identified as having at least one helminth species. A single infection was detected in 16.6% of cases, but a three species infection covered the highest rank (25%). All these helminths have been reported from other areas of Iran including the north, northeast and southwest, but not in Luristan. Among seven helminths identified, at least three species are transmissible to humans. The public health significance of these helminths is discussed.