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PubMed2004

Cryptosporidium parvum and other instestinal parasites among diarrhoeal patients referred to EHNRI in Ethiopia.

The occurrence of intestinal parasites in patients referred to the Parasitology Laboratory of the Ethiopian Health and Nutrition Research Institute (EHNRI), was recorded for four consecutive years, 1998-2001. Based on the stool appearance i.e. watery, loose, muciod and bloody, 442 diarrhoeal samples were particularly selected to allow diagnosis of intestinal parasites with emphasis on coccidian intestinal parasites. Wet saline mounts and formol ether concentration method with logul's iodine were performed for the detection of cysts, ova, trophozoites and larvae of intestinal parasites. Modified Ziehel Nelseen staining of stool smears was used to identify Cryptosporidum parvum and Isospora belli. The overall detection rate was 79.4% (351/442). The spectrum of positivity with any protozoa was 54.3% (240/442) and helminthes 25.1% (111/442). Cryptosporidium parvum was identified in 92/442 (20.8%). Isopora belli was identified among 35/442 (7.9%): Entamoeba histolytica/dispar scored second with positivity rate of 17.0% (75/442) and Giardia lamblia was found in 38/442 (8.6%) stool samples. As compared to protozoan parasites, detection rate with helminthes was very low. Among the helminthes. Strongyloides stercoralis was found in 38/442 (8.6%). This information strengthens the importance of intestinal protozoan parasites with recognition of the opportunistic parasites as major causes of diarrhoea. Their role in HIV/AIDS patients cannot be over-emphasized. Further awareness for the need of establishing different parasitological techniques at health service giving centers would enhance better understanding and management of diarrhoeal illness.

AIDS-Related Opportunistic Infections↗
PubMed2006

[Metazoan parasites of bream (Abramis brama Linnaeus, 1758) in Lake Durusu (Terkos)].

In this study, metazoan parasites of bream (Abramis brama Linnaeus, 1758) in the Lake Durusu (Terkos) were investigated between June 2002 and May 2003. During this study, a total of 67 bream were examined for the presence of metazoan parasites. Ten species of parasites were found on 64 of the 67 fish examined. These parasites are: Dactylogyrus sphyrna (Linstow, 1878) and D. distinguendus (Nybelin, 1936) Monogenoidea, Caryophyllaeus laticeps (Pallas, 1781) Cestoidea, Tetracotyle sp, Diplostomum sp. and Tylodelphys clavata (Nordmann, 1832) metacercaria Trematoda, Eustrongylides excisus (Jagerskiöld, 1909) Nematoda, Piscicola geometra (Linnaeus, 1758) Hirudinea, glochidia of mollusk, Bivalvia, Argulus foliaceus (L., 1758) Crustacea. Diplostomum sp., Dactylogyrus sphyrna and D. distinguendus were found to be the dominant parasites of A. brama. Both the prevalence and intensity of other parasites were not found to be high. All identified parasites are a new finding for A. brama in the Lake Durusu. This is the first time that D. distinguendus has been identified in Turkey.

Animals↗
PubMed1991

Influence of collection methods on the occurrence of alimentary canal helminth parasites in fish.

The effect of collecting trauma on the metazoan parasites in the alimentary canal of French grunts, Haemulon flavolineatum (Desmarest) (Perciformes: Haemulidae), was evaluated by comparing the number and species of parasites in 10-fish lots that were identical except for collecting technique. Collecting techniques included speared (dead), speared through the caudal peduncle (live), trapped, dipnetted at night, and ostracitoxin exposed. Dead, trapped, and toxin-stressed fish had no alimentary canal parasites, whereas speared-live and night-dipnetted fish had comparable numbers of parasites. Fish collected by using apparently traumatic techniques quickly expelled their alimentary canal metazoan parasites. Our results cast doubt on the reliability of traditional fish parasite surveys, studies on population dynamics of fish parasites, and experiments that employ these traumatic collecting methods.

Animals↗
PubMed1991

[Intestinal parasites in primary schools of different socioeconomic status and environmental conditions].

Two hundred ninety-four stool sample obtained from primary schools of different social status and environmental conditions were examined for intestinal parasite. The age range was between seven and 13 years, 43% of the patients were females and 57% of the patients were males. In our study it has been observed that the parasite incidence was 29.3%. The predominant parasite was Giardia intestinalis (15.7%). Enterobius vermicularis (10.5%) and Ascaris lumbricoides (2.3%) have been followed respectively. There were three different parasites in the primary school of good social status and environmental conditions. In the contrary in the village school, there were five different parasites. In the conclusion parasite incidence was high in our region. In primary schools of different conditions there were no difference Giardia intestinalis but there were marked difference in the other parasites.

Ascariasis↗
PubMedDate not supplied

[Parasitic rheumatism].

The joint manifestations of parasitic diseases are rare. They may be due to the presence of a parasite within one or severed joints, to involvement of a neighbouring joint, or distant involvement due to an immuno-allergic mechanism. The latter category constitutes what one may call parasitic rheumatism. The latter is characterised by arthropathies of inflammatory type with raised sedimentation rate, marked but inconstant hypereosinophilia, and total inefficacy of antirheumatic treatments. The diagnosis of parasitic rheumatism depends on these criteria, on the diagnosis of the parasitic disease in question, above all filariasis but also other parasitic diseases, and above all the great efficacy of specific anti-parasitic treatments.

Adult↗
PubMed1991

Immunological changes in opportunistic parasitic infections.

This study was done on 110 patients with different types of malignant diseases and 20 healthy controls. Cases were divided into four groups according to parasitological and serological examination. The first group included 37 patients without any parasitic infection, the second 28 patients with no opportunistic parasitic infection, the third group 33 patients with opportunistic parasitic infection while the fourth included 12 patients with mixed opportunistic and non opportunistic parasites. Immunological status was estimated by carrying out leucocyte migration inhibition test and intradermal skin test for cell mediated immunity and quantitative determination of immunoglobulins IgG, IgM and IgA for humoral immunity testing. It was found that cell mediated immunity was decreased in cancer patients compared with the normal control group. Super added parasitic infections lead to greater decrease. Opportunistic parasitic infection aggravated the condition more. Marked suppression of the cell mediated immunity was found in the group of cancer patients with mixed opportunistic and non opportunistic parasitic infections. IgG and IgA were increased in the first three groups and decreased in the mixed one, IgM was increased in the first and second groups while decreased in groups with opportunistic infections.

Humans↗
PubMed1987

Infection and mortality patterns in strains of oysters Crassostrea virginica selected for resistance to the parasite Haplosporidium nelsoni (MSX).

Strains of oysters Crassostrea virginica resistant to mortality caused by the parasite Haplosporidium nelsoni (MSX) were developed and tested through 6 generations. In addition, strains in each generation were followed for up to 6 yr of continuous exposure to the parasite in nature. Selected strains responded to challenge by the parasite with gradually improved survival in successive generations. They were slower to develop patent infections than were unselected groups and were able to delay mortality after infections did develop, but under repeated exposure most oysters eventually died with H. nelsoni parasitism. Many selected strains, however, reached market size before significant mortalities occurred. The data suggest that resistance to H. nelsoni mortality is under the influence of many genes. No clear defense mechanism has been described and we hypothesize that resistance to H. nelsoni may, in part, involve a physiological state in which selected oysters temporarily fail to provide a suitable habitat for the parasite. Temporary insusceptibility would, in this view, be followed by an increased ability to tolerate the parasite when conditions for its development are present. Selection would then favor individuals that are able to prolong periods of insusceptibility and/or to carry out basic life processes while parasitized.

Animals↗
PubMed1983

Host-parasite interactions which influence the virulence of Trypanosoma (Trypanozoon) brucei brucei organisms.

Subclones were prepared in mice from T. b. brucei ILTat 1.4 parasites. Subclones which did not differentiate to stumpy forms in mice were highly virulent and did not stimulate detectable antibody responses. A subclone which did give rise to stumpy forms in mice, was less virulent and did stimulate an antibody response specific for the trypanosome surface glycoprotein. Clones and subclones of T.b. brucei parasites which did not give rise to stumpy forms in mice, did give rise to stumpy forms in Bovidae. Plasma from cattle infected with those parasites did not stimulate differentiation of T.b. brucei parasites in mice. Murine pleomorphic and monomorphic T.b. brucei parasites retained their respective phenotypes in co-infected mice. Both types of parasites were equally pleomorphic in Bovidae. We conclude that some clones of T.b. brucei remain monomorphic in mice as a result of a high avidity interaction between slender forms and host molecules which inhibit differentiation of T.b. brucei parasites.

Animals↗
PubMed1984

Natural history of intestinal parasites in asymptomatic adults.

The need to treat asymptomatic adults who have intestinal parasites should be based on considerations of potential pathogenicity and transmission risk, but such data are sparse in general and unavailable for countries such as the United States, where reinfection is rare. Opinions of North American physicians about the natural history and treatment of 12 parasites detectable by stool examination were assessed using the Delphi technique. In response to the first questionnaire, majority agreement on pathogenic potential was achieved for only 3 of 12 parasites. When the more expert group was queried a second time, majority agreement was achieved for 8 of 12 parasites. Nevertheless, the predicted risk of subsequent disease still varied widely, from 1:10 to 1:1,000 for most parasites, and was unrelated to the perceived need for treatment. Almost all respondents thought asymptomatic adults with any intestinal parasites should always be treated. Transmission risk was judged to be low and was generally appropriate to the life cycle of the parasite.

Adult↗
PubMed1995

[Gastrointestinal and urinary parasitic infection in children at a regional hospital center in Togo: some epidemiological aspects].

To determine the impact of parasitic infection of the digestive and urinary tract in children living in a rural area of Togo, a retrospective study was conducted in a Pediatric Department of Kara, Togo. Results revealed that 35% of the 1610 children between the ages of 0 and 16 years had positive tests for parasites in stools or urine and that 117 had more than one parasite. Trichomonas intestinalis, Entamoeba histolytica, Schistosoma mansoni and Necator americanus accounted for 86.5% of the parasitic infections observed. Parasitic infection was observed during the neonatal period and its incidence increased in males up to the age of 12 years and during the rainy months of the year. Study of associated diseases indicated that 56% of children with parasites also had malaria and that 47% were anemic. Parasitic infection of the digestive and/or urinary tract was noted in 31.8% of children under the age of 5 years with malnutrition.

Adolescent↗
PubMedDate not supplied

[Present status and new approach to anti-parasite therapy].

New highly effective molecules have been developed for the treatment of human parasites due to the development resistances and newly described types of parasitosis. In man as in animals, chemoresistant strains of parasites are rare, even for Plasmodium species where decreased sensibility has been observed basically due to monotherapies given for too short periods. Many resistance mechanisms have been elucidated. Most antiparasite drugs are metabolized in the liver and alterations in the mitochondrial oxidative system, particularly in hepatic fasciolasis and amibiasis, may limit the production of active derivatives. Modifications in the host-parasite relations may also have an effect as has been observed in patients with acquired immunodeficiency syndrome. Several approaches suggest new therapeutic perspectives. Since most protozoa require large amounts of energy to maintain motility and asexual reproduction, blocking aerobic glycolysis has been suggested but is limited by toxic effects. Blocking protein metabolism is another possibility since intracellular protozoa cannot synthesize purines. Parasites also rely on the host for cholesterol, phospholipids and other lipids and blocking their uptake into the parasite is another possibility. Promising results have been obtained in vitro against Plasmodium berghei and P. chabaudi. Other approaches include inhibiting drug outflow from the parasite incapable of metabolizing it. Nonesense oligonuclides could be coupled with active drugs and induce irreparable damage to the parasite. In addition to these new therapeutic possibilities, better use of traditional drugs should be emphasized.(ABSTRACT TRUNCATED AT 250 WORDS)

Antimetabolites↗
PubMed1993

Endocrine and neuroendocrine host-parasite relationships.

The relationships between parasites and hosts are complex, with many of these interactions involving an amazing degree of biochemical coevolution and communication. Hormones, neurohormones, and growth factors figure prominently in these relationships. In vertebrate hosts, many parasites secrete hormones, neuropeptides, or cytokine-like molecules that influence the host's physiological and immunological responses. Alternatively, the parasites secrete factors that alter the host's hormone levels. Simultaneously, molecules emanating from the host strongly influence the parasites' success. In some cases the host's hormones directly influence the parasites; in others, effects are mediated indirectly via the host's immune system. In invertebrates, the presence of parasites likewise has a major influence on the host's endocrine status and the normal suite of processes governed by hormones, including host development, metamorphosis, and reproduction. In insects, interactions involving juvenile hormone and ecdysteroids are especially well-documented, and recent evidence suggests that neuropeptides may also be affected by parasitism. Moreover, recent data suggest that in some species, such as snails, the host's nervous, neuroendocrine, and immune systems are functionally linked, similar to the complex interactions seen in vertebrates.

Animals↗
PubMed1993

Immunoecological succession in host-parasite communities.

From the unique perspective of the parasite, each potential host exists as an ecosystem in its own right, comprised of biotic and abiotic components. If the parasite's limits of tolerance are not exceeded by the host environment, parasitism may occur. The organs of the host can be viewed as integrated communities comprised of distinct cell populations. Each population of cells occupies a unique ecological niche and contributes to the community in an essential way. The coordinated interactions among cells within each community and among the communities themselves are essential for the host to maintain itself in a homeostatic state. As with free-living systems in equilibrium, introduction of an exotic population into the community disrupts the balance, and ecological succession resumes until a new equilibrium is established. Such is the case when parasites invade the host. The successful invader must not exceed the carrying capacity of the environment nor modify the habitat so drastically that its own survival is compromised. The specific interactions that occur between invading parasites and the populations of cells that comprise the host's immune system can also be viewed in ecological terms. The successful parasite must "compete" with cells in the host community for available niches and avoid "predation" by cells of the host immune system. As is true for interactions among organisms in a free-living ecosystem, the outcome of the host-parasite interaction is not readily predicted from knowledge of the component parts in isolation.

Animals↗
PubMed1993

The ecology of animal parasitic nematodes in endemic areas of Jos, Nigeria.

A survey involving 3418 faecal samples collected from three areas of heavy human and animal activities in Jos, Nigeria showed that 2354 (68.9%) of the samples harboured various parasitic nematodes of man and animals. Altogether, twelve species of parasitic nematodes were encountered. Five of these, namely: Ascaris lumbricoides, Ancylostoma duodenale, Necator americanus, Trichuris trichiura and Strongyloides stercoralis infect man while five others: Trichostrongylus probolurus, T. colubriformis, Haemonchus contortus, Cooperia pectinata and Strongyloides papillosus are parasites of ruminants. Ancylostoma caninum and Trichuris suis parasitic in dogs and pigs, respectively, were also recorded. Generally these nematodes fluctuated with changes in ecological factors, especially rainfall and temperature. Whereas most of the human parasitic nematodes were encountered in the shaded areas, the open areas harboured more animal parasites, an indication that most human parasitic nematodes are more susceptible to deleterious environmental conditions. Aspects of zoonotic and public health significance are stressed.

Animals↗
PubMed1995

[Relationship between the rate of parasitic infection and the knowledge of prevention].

The relationship between the rate of parasitic infection and the level of knowledge of prevention was studied among 5479 persons allocated to 12 randomly selected groups. Stools were examined for parasitic infection by using Kato-Katz, iodine direct smear amd tube culturing methods. Children under 15 were examined for Enterobius infection by cellophane tape method. Individuals were considered infected when any parasite species was found in the stool and the infection rate was computed. The score on knowledge of prevention was measured by devising a questionnaire comprising 11 questions on parasitic disease transmission, clinical signs and prevention methods. Ten marks were given for each question correctly answered. The result of the investigation showed that the total infection rate was 52.2% and there was no significant difference between males and females (X2 = 1.94, P > 0.05). The infection rate increased with a decrease in the level of education and the highest was found in 5-year-old age group. There were altogether 7 species of parasites detected in all age groups. The infection rate of Ascaris lumbricoides was 31.3%; Trichuris trichiura, 34.1%; hookworm, 5.3%; Enterobius vermicularis, 20.3%(227+1 117); Fasciolopsis buski, 0.8%; Entamoeba coli, 0.8%; Giardia lamblia, 0.2%. The average score on knowledge was 41.9, being significantly higher in males than in females. Analysis for the age distribution showed that the highest score was found in 15-year-old age group. The data of infection rate of different parasites were converted by arcsine transformation and compared with the average score, showing that there were negative relations between the average score and the infection rate of Trichuris, hookwork, Entamoeba and the total incidence. The value of r was --0. 5534, --9.5557, --0.6091 and --0.604. respectively. The number of parasite species infecting individuals was also found to have negative relation to the score on knowledge of prevention.

Adolescent↗
PubMed1997

Survival and reproductive output of Chironomus tentans (Diptera: Chironomidae) in response to parasitism by larval Unionicola foili (Acari: Unionicolidae).

Parasitic associations between larval Unionicola foili and the dipteran Chironomus tentans were established in the laboratory, and the effects of these water mite larvae on survival and reproduction of C. tentans were determined. Longevity of parasitized insects was not significantly different from those that were unparasitized. Furthermore, there was no significant difference in the onset of oviposition between parasitized and unparasitized female chironomids. However, infected females oviposited significantly more eggs compared to uninfected controls. This study contradicts others indicating that water mite larvae severely reduce the survivorship and reproductive output of insects. The results are consistent with analyses indicating that degree of parasitism is not correlated with either duration of the parasitic phase or longevity of larvae following their parasitic association with chironomids. Larval U. foili apparently secure sufficient nutritional resources to complete their development, yet their hosts still exhibit fitness components expected for unparasitized individuals. Extreme site specificity exhibited by larval U. foili may limit the degree of parasitism on host insects and in doing so preclude larval mites from achieving infection levels that could negatively impact host survival and reproduction.

Acari↗
PubMedDate not supplied

[Intestinal parasite infections in a periurban community from the Province of Buenos Aires, Argentina].

A survey for intestinal parasites was performed on 38 individuals within the urban area of La Plata City (Province of Buenos Aires, Argentina). This community is composed of brick-factory workers who also live in the factory premises. An analysis for intestinal parasites was done on fecal samples collected serially and by means of anal swabs and thereafter preserved in formol solution. At the same time, the occurrence of the parasites under study as well as that of commensal organisms was investigated in water and soil samples within the factory environs. Information was also obtained from the members of this community as their age, sex, birthplace, and recent travels, either abroad or to the interior of Argentina. The prevalence of the pathogens and commensal parasites was 89.5%. The frequency of protozoans and helminths was: G. lamblia 26.3%, B. hominis 65.8%, A. lumbricoides 7.9%, H. nana 2.6%, Uncinaria sp. 7.9%, S. stercoralis 2.6% and E. vermicularis 42.1%. None of these parasite or commensal organisms were present in the water samples investigated. Four out of 20 soil samples analyzed contained parasitic elements: T. canis eggs (one), G. lamblia cysts (two) and A. lumbricoides eggs (one). These results indicated that most important factors causing such a high prevalence of coproparasites were the poor conditions of personal and community hygiene in combination with the frequent travels to the north and the northeast of the country, regions which are endemic parasitic areas. The implementation of programs on health education and communal sanitation would contribute in the control of this health problem.

Adolescent↗
PubMed1997

[The cell biology of amebas and ameba-flagellates--parasites of man and animals].

The majority of parasitic amoebae and amoeba-flagellates are facultative parasites of animals and humans and only a few of them are obligate parasites (see reviews: Sopina, 1997; Visvesvara, Stehr-Green, 1990). Among the latter Entamoeba histolytica and among the former Naegleria fowleri and several species of Acanthamoeba are most dangerous for humans. It is still unclear whether Balamuthia mandrillaris, pathogenic for monkeys and humans, may be either obligate or facultative parasite (Visvesvara et al., 1993). Endolimax nana and Iodamoeba butschlii are commensals of humans and some animals. This review is devoted to cell biology of the above genera to provide a better understanding of cell-biological aspects of interrelations between these parasites and their hosts. In the Russian text-books on medical and veterinary parasitology these parasitic protozoa have never been regarded in terms of cell biology, and the available information seems to become out of date. This review is aimed to fill these gaps. Evidence on the ultrastructure of the above parasites, in particular that of their mitotic chromosomes, mechanisms of attachment to substratum of many of these, of locomotion and endocytosis, is provided and discussed in addition to the problem of differentiation of Naegleria amoebae into flagellates.

Amebiasis↗