MyMedR

Displaying publications 41 - 46 of 46 in total

Abstract:

Sort:

Fulltext Proteinases in Naegleria Fowleri (strain NF3), a pathogenic amoeba: a preliminary study

Mat Amin N

Trop Biomed, 2004 Dec;21(2):57-60.
PMID: 16493399

Naegleria fowleri is a free-living amoeba, known as a causative agent for a fatal disease of the central nervous system (CNS) in man such as Primary amoebic meningoencephalitis (PAM). Factors contributing to its pathogenicity and its distribution in the environment have been investigated by previous researchers. In case of its pathogenicity, several enzymes such as phospolipase A and sphingomyelinase, have been proposed to probably act as aggressors in promoting PAM but no study so far have been conducted to investigate the presence of proteinase enzyme in this amoeba although a 56kDa cystein proteinase enzyme has been identified in Entamoeba histolytica as an important contributing factor in the amoeba's virulence. In this preliminary study, a pathogenic amoeba, Naegleria fowleri (strain NF3) was examined for the presence of proteinases. Samples of enzymes in this amoeba were analysed by electrophoresis using SDS-PAGE-gelatin gels. The results showed that this amoeba possesses at least two high molecular weight proteinases on gelatin gels; their apparent molecular weights are approximately 128 kDa and approximately 170 kDa. Band of approximately 128 kDa enzyme is membrane-associated and its activity is higher at alkaline pH compared with lower pH; at lower pH, its activity is greatly stimulated by DTT. The approximately 170 kDa band enzyme appears to be inactivated at pH 8.0, at lower ph its activity is higher and DTT-dependance. The activity of this enzyme is partially inhibited by inhibitor E-64 but markedly inhibited to antipain suggesting it belongs to the cysteine proteinase group.

Matched MeSH terms: Entamoeba histolytica
Fulltext Important zoonotic intestinal protozoan parasites in Asia

Mak JW

Trop Biomed, 2004 Dec;21(2):39-50.
PMID: 16493397

Intestinal protozoa are increasingly being studied because of their association with acute and chronic diarrhoea in immunocompromised as well as immunocompetent patients. Various community outbreaks due to contamination of water or food with these protozoa have further highlighted their importance in public health. Among these important pathogens are Giardia duodenalis, Entamoeba histolytica, Cryptosporidium parvum, Cyclospora cayetanensis, Isospora belli, and microsporidia. Except for the cyst-forming G. duodenalis and E. histolytica, the others are intracellular and form spores which are passed out with the faeces. These organisms are also found in various animals and birds and zoonotic transmission is thought to occur. These infections are distributed worldwide, with a higher prevalence in developing compared to developed countries. However, the relative importance of zoonotic infections especially in developing countries has not been studied in detail. The prevalence rates are generally higher in immunodeficient compared to immunocompetent patients. Higher prevalence rates are also seen in rural compared to urban communities. Most studies on prevalence have been carried out in developed countries where the laboratory and other health infrastructure are more accessible than those in developing countries. This relative inadequacy of laboratory diagnosis can affect accurate estimates of the prevalence of these infections in developing countries. However, reports of these infections in travellers and workers returning from developing countries can provide some indication of the extent of these problems. Most studies on prevalence of amoebiasis in developing countries were based on morphological identification of the parasite in faecal smears. As the pathogenic E. histolytica is morphologically indistinguishable from that of non-pathogenic E. dispar, estimates of amoebiasis may not be accurate. The epidemiology of human microsporidia infections is not completely understood. Two species, Enterocytozoon bieneusi and Encephalitozoon intestinalis, are associated with gastrointestinal disease in humans and it is believed that human to human as well as animal to human infections occur. However, the importance of zoonotic infections has not been fully characterised. G. duodenalis cysts, microsporidia and Cryptosporidium oocysts have been detected in various ground water resources, but their role in community outbreaks and maintenance of the infection has not been fully characterised. The taxonomic classification and pathogenic potential of B. hominis are still controversial. While considered by many as yeast, fungi or protozoon, recent sequence analysis of the complete SSUrRNA gene has placed it within an informal group, the stramenopiles. This review covers recent published data on these zoonotic infections and examines their public health importance in Asian countries.

Matched MeSH terms: Entamoeba histolytica
Intestinal parasitic infections frequency in referred patients to a large teaching hospital, Khuzestan, Southwest, Iran, 2017

Feiz Haddad MH, Maraghi S, Ali SA, Feiz Haddad R, Nasser Zadeh R

Trop Biomed, 2018 Dec 01;35(4):915-925.
PMID: 33601841

Intestinal parasitic infections (IPIs) are among the most important infectious diseases in Iran. A cross sectional study was designed to determine frequency of intestinal parasites among referrals to a large teaching hospital in Khuzestan, Southwest of Iran, 2017. A total number of 5613 stool samples were examined through direct smear and formalin-ether concentration methods to detect possible parasitic infections. Samples consisted of 2643 (47.09%) male and 2970 (52.91%) female. A total of 1468 (26.15%) samples were positive (13.11% male and 13.4% female) and 4145 (73.85%) were negative. The results also showed that 255 of samples had more than one type of parasite (mix infections). Counting single and mix parasite infections, the total number of positive cases reached to 1723. Helminthes parasites were present in 12 (0.7%) cases, while intestinal protozoan parasites were in 1711 (99.3%) cases. Almost equally, pathogenic and nonpathogenic parasites infected 860 (49.91%) and 863 (50.09%) of patients, respectively. The frequency for helminthes was determined at 0.52% with Hymenolepis nana and Enterobius vermicularis however, Giardia lamblia in 38.54% and Entamoeba histolytica/dispar at 10.68% were concluded as protozoa elements. The IPIs frequency was recorded in female and male patients at 49.16% and 50.14%, respectively. According to the current results the infection rate of intestinal parasites has been significantly reduced especially for helminths infections in this region possibly due to public attention to health issues such as; increased awareness of people, improvement of sanitation, seasonal variations, health education and personal hygiene.

Matched MeSH terms: Entamoeba histolytica
Prevalence and risk factors for infection with Entamoeba histolytica/dispar/ moshkovskii complex in people living in the slightest and outermost islands of Indonesia

Junaidi -, Asmaruddin MS, Kurrohman T, Nurdin -, Khazanah W

Trop Biomed, 2023 Jun 01;40(2):160-164.
PMID: 37650401 DOI: 10.47665/tb.40.2.005

Entamoeba histolytica (E. histolytica), the causative agent of amoebiasis, is still a global public health problem that cannot be controlled, especially in tropical and subtropical countries. This study was conducted to obtain information about the incidence of Entamoeba histolytica/dispar/ moshkovskii complex infection and the factors that influence it. The prevalence of infection with the Entamoeba histolytica/dispar/moshkovskii complex and the factors that influence it in people living on the smallest and outermost island of Indonesia, Sabang Island, Aceh Province. This study involved 335 respondents aged >= 10 years. Respondents were selected by non-probability sampling technique. Interviews and observations were conducted to identify risk factors. The Entamoeba histolytica/dispar/ moshkovskii complex was identified by direct examination, concentration, and Whitley's trichrome staining techniques. A Chi-Square test was performed to analyze the correlation of risk factors with the incidence of infection. The prevalence of infection with the Entamoeba histolytica/dispar/ moshkovskii complex in the people of Sabang Island was 26.6% (89/335). Source and adequacy of clean water correlated with the incidence of Entamoeba histolytica/dispar/moshkovskii complex infection. Demographic variables are not correlated with the incidence of infection. However, the group of women aged > 61 years, unemployed, unmarried, and earning less than the regional minimum wage tend to be more likely to be found with Entamoeba histolytica/dispar/moshkovskii complex infections. Thus it can be concluded that the prevalence of infection with the Entamoeba histolytica/dispar/moshkovskii complex on Sabang Island is in the high category. The prevalence of E. histolytica as the causative agent of amoebiasis cannot be explained with certainty because the two identical non-pathogenic Entamoeba species cannot be distinguished by microscopic identification. Sources and adequacy of clean water correlate with the incidence of Entamoeba histolytica/dispar/moshkovskii complex infection in the people of Sabang Island.

Matched MeSH terms: Entamoeba histolytica*
Summary of recent abstracts. II. Amoebiasis and intestinal protozoal infections

Apted FI

Trop Dis Bull, 1973 Feb;70(2):105-17.
PMID: 4349730
Matched MeSH terms: Entamoeba histolytica
First molecular epidemiology of Entamoeba histolytica, E. dispar and E. moshkovskii infections in Yemen: different species-specific associated risk factors

Al-Areeqi MA, Sady H, Al-Mekhlafi HM, Anuar TS, Al-Adhroey AH, Atroosh WM, et al.

Trop Med Int Health, 2017 04;22(4):493-504.
PMID: 28151567 DOI: 10.1111/tmi.12848

OBJECTIVES: To investigate the molecular epidemiology of Entamoeba histolytica, E. dispar and E. moshkovskii infections among rural communities in Yemen.
METHODS: In a community-based study, faecal samples were collected from 605 participants and examined by wet mount, formalin-ether sedimentation, trichrome staining and nested multiplex PCR techniques. Demographic, socio-economic and environmental information was collected using a pre-tested questionnaire.
RESULTS: Overall, 324 (53.6%) of the samples were positive for Entamoeba cysts and/or trophozoites by microscopic examination. Molecular analysis revealed that 20.2%, 15.7% and 18.2% of the samples were positive for E. histolytica, E. dispar and E. moshkovskii, respectively. Multivariate analysis showed different sets of species-specific risk factors among these communities. Educational level was identified as the significant risk factor for E. histolytica; age and gender were the significant risk factors for E. moshkovskii; and sources of drinking water and consumption of unwashed vegetables were the significant risk factors for E. dispar. Moreover, living in coastal/foothill areas and presence of other infected family members were risk factors for both E. histolytica and E. moshkovskii infections.
CONCLUSION: The study reveals that Entamoeba spp. infection is highly prevalent among rural communities in Yemen, with E. histolytica, E. dispar and E. moshkovskii differentiated for the first time. Identifying and treating infected family members, providing health education pertinent to good personal and food hygiene practices and providing clean drinking water should be considered in developing a strategy to control intestinal parasitic infections in these communities, particularly in the coastal/foothill areas of the country.

Matched MeSH terms: Entamoeba histolytica/genetics