Intestinal Protozoan Infections Research Articles

Survey of Gastrointestinal Parasitic Infections in Quarantined Dogs in Taiwan

Intestinal helminth and protozoan infection in the quarantined dogs in Taiwan were examined using fecal examination between January to December, 2004. Of the 376 dogs imported from 11 countries, 63 (16.8%) were found to be infected with at least one species of intestinal parasite. The parasites detected were oocysts of Isospora canis and eggs of Toxocara canis, Trichuris vulpis and hookworms. Of the 63 infected dogs, 11 were found to have a mixed infection of two different species of parasites. This paper illustrates that parasites are transmitted from one country to another through the transport of animals. Moreover, there is also a possibility of parasitic infection among quarantined dogs as well as the zoonotic potential for quarantine officers during the quarantine period.

Intestinal Parasite Infestation in HIV Infected Patients

One of the major health problems among HIV-infected patients is the intestinal parasite infestations. It can be seen that intestinal helminth infestation in HIV-infected patients is common. However, the reported prevalence is usually similar to those of non HIV-infected patients in the same setting. The infestations are ordinary not opportunistic, hence, thus usually show no correlation to immune status of the patients. The suppression of immunity due to HIV infection shows no significant role in increasing the intestinal helminth infestations. On the other hand, having occult intestinal helminth infestations does also not worsen the outcome of HIV infection. Concerning the clinical manifestation, most of the helminth infestations are asymptomatic and the diagnosis is usually based on the stool examination. Treatments of the infestations as well as the outcomes are usually similar to immunocompetent host. Intestinal protozoa infestations are also important problems for HIV-infected patients. Some infections are ordinary, while the others are opportunistic infection. The important opportunistic intestinal parasites including C. parvum, I. belli, Cyclospora and the Microsporidia are found at high prevalence among the HIV-infected patients, especially in low immune cases with persistent diarrhea. Concerning the clinical manifestation, most of the infestations bring diarrhea and the diagnosis is usually based on the stool examination with special stains. The treatment of the opportunistic infection can usually get control of the present illness but not prevent the re-infection. Luckily, with the present wide distribution of HAART, the prevalence of the opportunistic intestinal protozoa infections is significantly decreased.

Recent Advances in Immunomodulation and Vaccination Strategies Against Coccidiosis

Coccidiosis is a ubiquitous intestinal protozoan infection of poultry seriously impairing the growth and feed utilization of infected animals. Conventional disease control strategies rely heavily on chemoprophylaxis, which is a tremendous cost to the industry. Existing vaccines consist of live virulent or attenuated Eimeria strains with limited scope of protection against an ever-evolving and widespread pathogen. The continual emergence of drug-resistant strains of Eimeria, coupled with the increasing regulations and bans on the use of anticoccidial drugs in commercial poultry production, urges the need for novel approaches and alternative control strategies. Because of the complexity of the host immunity and the parasite life cycle, a comprehensive understanding of host-parasite interactions and protective immune mechanisms becomes necessary for successful prevention and control practices. Recent progress in functional genomics technology would facilitate the identification and characterization of host genes involved in immune responses as well as parasite genes and proteins that elicit protective host responses. This study reviews recent coccidiosis research and provides information on host immunity, immunomodulation, and the latest advances in live and recombinant vaccine development against coccidiosis. Such information will help magnify our understanding of host-parasite biology and mucosal immunology, and we hope it will lead to comprehensive designs of nutritional interventions and vaccination strategies for coccidiosis.

Estudo soroepidemiológico da cisticercose humana em um município do Estado do Piauí, Região Nordeste do Brasil

As part of parasitological studies in the area surrounding the Serra da Capivara National Park, Piauí State, Northeast Brazil, from 1999 to 2001, the current study aimed to evaluate the epidemiological profile of human cysticercosis in the Municipality of João Costa. Clinical and epidemiological data were obtained, and blood samples were drawn for immunoenzymatic serological tests (ELISA and Western blot), using Taenia crassiceps as the antigen. The first stage, in 1999, investigated 169 individuals with a confirmed history or suspicion of infection/disease involving the teniasis/cysticercosis complex, along with the family members. Some 13.6% of the individuals were seroreactive for cysticercosis by the ELISA method. The second stage, in 2001, evaluated 92 serum samples of individuals who had been detected as reactive for cysticercosis in the first stage, along with their family members; 24% of the samples were reactive to cysticercosis by ELISA and 29% by Western blot. During this same stage a coprological survey was performed with 701 individuals, including volunteers. Prevalence of intestinal parasites was 51%, with a higher prevalence of protozoans (95%) than helminths (5%). The results indicate the endemicity of cysticercosis in the area, in addition to the high frequency of intestinal protozoan infections.

Zur Labordiagnostik von Entamoeba histolytica-Infektionen. The laboratory diagnosis of Entamoeba histolytica-infections

Zusammenfassung Zusammenfassung Die klassische Stuhlmikroskopie zum Nachweis intestinaler Protozoen-Infektionen wird mehr und mehr ersetzt durch neue Detektionsverfahren wie Immunfluoreszenz, Antigen-ELISA oder PCR. Dies gilt insbesondere für die Diagnostik von Entamoeba histolytica, da dieser Parasit mikroskopisch nicht von anderen, apathogenen Amöbenspezies wie Entamoeba dispar oder Entamoeba moshkovskii unterschieden werden kann.

Effect of Giardia infection on growth and psychomotor development of children aged 0-5 years.

Giardiasis, an intestinal protozoan infection caused by Giardia intestinalis, is common in southeastern Anatolia, Turkey. In this cross-sectional survey, to investigate the role of giardiasis on growth and psychomotor development, we studied 160 children aged 0-5 years. Data were collected using a structured questionnaire, anthropometry, Ankara Developmental Screening Inventory, and laboratory analysis of fecal samples. The results showed that 50 per cent of the subjects were infected with at least one pathogen of intestinal parasitic infections. Giardia intestinalis was the most frequent pathogenic parasite. Giardia-infected children had a risk for stunted (OR = 7.67, 95 per cent CI = 2.25-26.16; p = 0.001) and poor psychomotor development (OR = 2.68, 95 per cent CI = 1.09-6.58; p = 0.030). The data indicate that Giardia intestinalis infection has an adverse impact on child linear growth and psychomotor development. In the primary healthcare centers, during the programme of the monitoring growth and developmental status of children, following children in terms of Giardia, diagnosis and treatment will have a positive effect on child health.

Application of biotechnological tools for coccidia vaccine development

Coccidiosis is a ubiquitous intestinal protozoan infection of poultry seriously impairing the growth and feed utilization of infected animals. Conventional disease control strategies have relied on prophylactic medication. Due to the continual emergence of drug resistant parasites in the field and increasing incidence of broiler condemnations due to coccidia, novel approaches are urgently needed to reduce economic losses. Understanding the basic biology of host-parasite interactions and protective intestinal immune mechanisms, as well as characterization of host and parasite genes and proteins involved in eliciting protective host responses are crucial for the development of new control strategy. This review will highlight recent developments in coccidiosis research with special emphasis on the utilization of cutting edge techniques in molecular/cell biology, immunology, and functional genomics in coccidia vaccine development. The information will enhance our understanding of host-parasite biology, mucosal immunology, and host and parasite genomics in the development of a practical and effective control strategy against Eimeria and design of nutritional interventions to maximize growth under the stress caused by vaccination or infection. Furthermore, successful identification of quantitative economic traits associated with disease resistance to coccidiosis will provide poultry breeders with a novel selection strategy for development of genetically stable, coccidiosis-resistant chickens, thereby increasing the production efficiency.

Intestinal parasitic infection and associated symptoms in children attending day care centres in Trujillo, Venezuela.

To examine the presence of intestinal protozoan and helminth infections and their association with clinical signs and symptoms in children in Trujillo, Venezuela. Conventional microscopic methods (thick-smear, saline and iodine solutions) were used to identify parasites in stool samples of 301 children attending day care centres. A subgroup of 45 children was evaluated clinically and parasitologically five times during a 1-month period using conventional methods and the Kinyoun acid-fast stain for Cryptosporidium identification. The point prevalence of protozoan infections was 21% for Giardia duodenalis, 1.0% for Entamoeba histolytica/dispar, 4% for Entamoeba coli, 16% for Blastocystis hominis, and 89% for Cryptosporidium parvum. Prevalence of helminth infection was 11% for Ascaris lumbricoides, 10% for Trichuris trichiura, 0.3% for Strongyloides stercoralis, and 1.3% for Hymenolepis nana. Over a 1-month time frame, new infections were observed at a rate of 11% for G. duodenalis, 4% for E. histolytica/dispar, 7% for A. lumbricoides, 11% for T. trichiura, 0% for S. stercoralis, and 2% for H. nana. Intestinal symptoms (diarrhoea, vomiting, gas, stomach pain, and loss of appetite) were associated with presence of one or more of C. parvum or B. hominis organisms in stool samples. Intestinal parasitic infections contribute significantly to the enteric disease burden experienced by this group of children. The organisms most strongly implicated by this study are common and difficult-to-treat protozoan pathogens.

Predictors and nutritional consequences of intestinal parasitic infections in rural Ecuadorian children.

The study investigated the prevalence, risk factors, and nutritional consequences of intestinal parasitic infections (IPI) in rural Ecuadorian children. A total of 244 children aged 0.2-14 years were studied. The data were collected using a structured questionnaire, anthropometry, and laboratory analysis of blood and fecal samples. The results showed that 90 per cent of the subjects were infected with at least one pathogenic IPI: 51 per cent with helminths, 37.6 per cent with protozoa, and 21.4 per cent with both. Giardia-infected children had a risk for stunted growth that was twice that of other children (51.7 vs. 33.1 per cent; OR = 2.16, 95 per cent CI = 1.13-4.15; p = 0.01). They also had significantly reduced mean hemoglobin levels compared with their non-infected counterparts (11.8 +/- 1.5 vs. 12.2 +/- 1.4 g/dl; p = 0.023). However, the proportion diagnosed with iron-deficiency anemia was slightly, but not significantly, increased (29.4 vs. 24.3 per cent). The most consistent predictor of Giardia and other protozoal IPI risk was a high intra-/peri-domicilliary concentration of domestic animals. Children who lived in such households had an infection risk that was two to five times greater than that of their non-infected counterparts. The data indicate that Giardia intestinalis infection has an adverse impact on child linear growth and hemoglobin. They also suggest that domestic animals may be an important reservoir for Giardia and other intestinal protozoal infections observed in the Ecuadorian children studied.

Serological levels of zinc, copper and iron elements among Giardia lamblia infected children in Turkey.

Giardiasis, an intestinal protozoan infection caused by Giardia lamblia, is common in Turkey, especially among children aged between 2- and 14-years-old. Effects of giardiasis on serological levels of zinc, copper and iron elements were assessed in this study. A total of 45 children, aged between 2- and 14-years-old, who were admitted to the Pediatrics Department of Celal Bayar University Medical School with gastrointestinal complaints and diagnosed as having giardiasis by stool examinations in the Parasitology Department, were enrolled as the study group (SG). The control group (CG) consisted of 45 age-matched healthy children. Serological levels of zinc, copper and iron were measured by atomic absorption spectrophotometer in all samples. As a result of the study, serum zinc levels were 67.43 +/- 17.72 microg/dL and 145.20 +/- 9.13 microg/dL, copper levels were 198.45 +/- 39.14 microg/dL and 150 +/- 21.14 microg/dL and iron levels were 87.98 +/- 18.31 microg/dL and 160.45 +/- 45.40 microg/dL, in SG and CG, respectively. When compared separately as SG and CG, there was a statistically significant difference between the serological levels of all these elements. These results revealed that giardiasis increased the serological levels of copper, like other infectious agents. However, zinc and iron levels decreased during giardiasis due to malabsorption.

Polyparasitism with Schistosoma mansoni, geohelminths, and intestinal protozoa in rural Côte d'Ivoire.

Single species infections with schistosomes, geohelminths, and intestinal protozoans are common over large parts of sub-Saharan Africa, and it is expected that polyparasitism affects a considerable proportion of the population, hence posing a great toll on public health. However, few investigations have been carried out to quantify the extent of polyparasitism. Here, a detailed assessment is reported for the epidemiology of Schistosoma mansoni, geohelminths, and intestinal protozoan infections, with particular emphasis on polyparasitism among 260 community members in rural Cĵte d'Ivoire. Schistosoma mansoni, Entamoeba coli, and hookworm were the predominant species with prevalences of 71.5, 64.6, and 51.9%, respectively. Only 8 individuals displayed no infection, whereas two-thirds of the population harbored 3 or more parasites concurrently. There were a series of significant pairwise parasite co-occurrences, e.g., between S. mansoni and hookworms and between S. mansoni and E. coli. It is concluded that polyparasitism in the population studied here was very common, which is probably the case also in other areas of rural Cĵte d'Ivoire and elsewhere in sub-Saharan Africa. These findings call for integrated approaches to effectively control multiple parasitic and protozoan infections.

Parasitic infections of the intestine.

Intestinal protozoal infections cause significant disease not only in the tropics but also in immunocompromised hosts and returning travellers in the developed world. Precise diagnosis of protozoal intestinal infection by microscopy can be difficult. Enzyme immunoassays for antigen detection are being used for some protozoal infections with some limitations which will, it is hoped, be overcome by molecular techniques. Nucleic acid amplification techniques could help improve detection of microsporidial species, which are difficult to detect microscopically and allow differentiation between Entamoeba histolytica and Entamoeba dispar. Definitive treatment for Cryptosporidium parvum infection remains elusive but new drugs are being evaluated. Cessation of thiabendazole production should not affect therapy of intestinal nematode infections as potent alternative therapy is available.

Incidence of Entamoeba histolytica/ Entamoeba dispar in International Travelers, Extracommunitary Immigrants, and Adopted Children

Imported tropical infections have become a serious health problem in industrialized countries, and have greatly contributed to the birth of a new branch of medicine called travel medicine. Several specific factors play an important role in this pathology, including the progressive and constant increase of subjects who travel to tropical and subtropical countries for various reasons (tourism, job, missionary institutions, etc.), the extracommunitary, often underground, flow of immigration, and the adoption of children from the same areas. A high percentage of imported tropical pathology is constituted by intestinal helminthic and protozoan infections, in particular those due to the Entamoeba histolytica / Entamoeba dispar complex. The aim of our study was to evaluate E. histolytica / E. dispar incidence in a casuistry composed of international travelers (IT), adult immigrants (AI), and adopted children (AC) collected from 1994–1999.

A survey of gastro-intestinal parasites of wild animals in captivity in the V.O.C. Park and Mini Zoo, Coimbatore

Indian zoo animals are exposed to and susceptible to many parasitic diseases, a fact of much concern albeit few data from cursory examination and postmortem studies. A typical mini zoo in Coimbatore was surveyed for gastro-intestinal parasites of wild animals by examining 60 fecal samples. The examination revealed a high percentage (58%) of captive animals were positive specifically for helminth parasitic infections and some (6%) were positive for protozoan infections. Strongyle, Trichuris, Strongyloides as well as Coccidia were present in case of herbivores and Toxocara, Ancylostoma as well as Artyfechinostomum in case of carnivores. with solution containing 5% formalin and 2% potassium dichromate. Then the samples were brought to the laboratory, processed using the concentration method of centrifugatio n- cum-sedimentation technique and examined for parasitic infections. The results are presented in Table 1. Results and Discussion The results of host-wise examination of the faecal samples are incorporated in Table 1. Out of the 60 animals examined 35 (58%) were found to be positive for parasitic infections, of which all 35 animals had helminth infection and three (6%) animals also had intestinal protozoan infection. Among helminthic infections, the prevalence of nematode infections was higher when compared to those of cestode and trematode infections. Among the infected animals, herbivores showed multiple infections with more than one helminth parasite. Strongyle and Trichuris were the most commonly found parasite ova in the herbivores. Other infections observed in herbivores were ascarid, Moniezia, spirurid, Strongyloides, Coccidia and Balantidium. Among carnivores, Toxocara and Ancylostoma were the significant infections specifically present. Other infections such as spirurid, Strongyloides and Artyfechinostomum were also observed in carnivores. The existing infections can be controlled by adopting suitable antihelmintic therapy and managemental procedures, but the possibility of recurrence is always there due to stress and also due to the closer proximity animals in a very small area. The possibility of transmission of zoonotic infections among the animals and the keepers also exist and requires investigation.

Intestinal amoebiasis, giardiasis and geohelminthiases: their association with other intestinal parasites and reported intestinal symptoms

In order to determine reported signs and symptoms that may predict an intestinal parasitic infection, 241 schoolchildren in western Côte d'Ivoire were interviewed with a simple questionnaire and their stool specimens were examined over several consecutive days. Special emphasis was placed on (i) assessing infections by Entamoeba histolytica/ E. dispar, Giardia duodenalis and by intestinal worms, (ii) looking for associations between these parasites, and (iii) looking for associations between these parasites and commonly perceived intestinal signs and symptoms. Complete questionnaire results, intestinal helminth infections derived from 4 Kato-Katz thick smears, and intestinal protozoa infections assessed on a single day by a formalin-ether concentration procedure were obtained from 209 children (87%). A logistic regression modelling approach showed that an infection with E. histolytica/ E. dispar was significantly associated with an Entamoeba coli infection. However, for G. duodenalis, hookworm and Ascaris lumbricoides, no association was found between any of these parasites and other intestinal parasites. In a multivariate analysis reported diarrhoea was the only symptom positively associated with an E. histolytica/ E. dispar infection ( P = 0·028). Its diagnostic performance showed a low sensitivity (28%), a high specificity (85%) and moderate positive and negative predictive values (52% and 67%, respectively). Surprisingly, reported ‘turning stomach’ was less often reported by children infected with G. duodenalis (borderline significance, P = 0·057). It is concluded that reported diarrhoea could be a symptom worth exploring further for the rapid identification of schoolchildren infected with E. histolytica/ E. dispar.

Diagnosis of intestinal protozoal infections. a comparison of parasitological examination in fresh and SAF-preserved stool specimens

Diagnosis of intestinal protozoal infections. a comparison of parasitological examination in fresh and SAF-preserved stool specimens

Mannose binding lectin genotype as a risk factor for intestinal protozoal infection in AIDS

Background Mannose binding lectin (MBL) is a multi-chain serum lectin with up to six 96 kDa subunits which plays an important role in non-specific defence against invasive organisms expressing polysaccharides terminating in mannose or N-acetyl glucosamine residues. Deficiencies of MBL predominantly arise from mutations in exon 1 of the MBL gene, at codons 52, 54 or 57. MBL gene mutations are over-represented in H1V positive populations, and are associated with shortened survival in AIDS. We examined MBL gene mutations in Zambian patients with AIDS related diarrhoea in order to determine whether they are associated with enhanced risk of enteric protozoal infections which might confer shortened survival. Methods 73 HIV seropositive patients with diarrhoea of over three weeks duration underwent stool microscopy, duodenal biopsy for evaluation of infection, and serum sampling. DNA was extracted from one frozen biopsy and used as the template for PCR amplification of exon 1; mutations were detected by controlled annealing of the products with a universal heteroduplex generator followed by polacrylamide electrophoresis. MBL concentrations in serum were assayed by ELISA. Results C. parvum was detected in 27%, L belli in 29%, and microsporidia in 32%. 46 of these patients had wild type MBL gene sequences, 20 were heterozygotes for the 57 codon mutation and 6 were homozygotes. MBL concentrations in serum were 1137 ~tg/l in wild types, 326 in heterozygotes, and 108 in homozygotes (p=0.0001). Individuals with MBL homozygous 57 codon mutations or 57/52 double mutations were at higher risk of cryptosporidiosis (Risk Ratio 3.1; 05%CI 1.6,6.0; p=0.006) but not of the other infections. Genotype predicted cryptosporidiosis, but serum MBL concentration did not. Conclusion In these AIDS patients, MBL mutations conferred higher risk for cryptosporidiosis than the wild type. No extra risk of other protozoal infection was observed. This extra risk for cryptosporidiosis could partially explain the shortened survival in AIDS experienced by individuals with MBL gene mutations.

Nitazoxanide in the treatment of patients with intestinal protozoan and helminthic infections: a report on 546 patients in egypt

Nitazoxanide, a new broad-spectrum antiprotozoal/anthelmintic drug, was tested in 546 patients with single or multiple intestinal protozoan and helminthic infections. After inclusion in the study, patients at least 12 years of age were instructed to take one nitazoxanide 500-mg table every 12 hours for 3 consecutive days. The guardians of the children aged 4 to 11 years were instructed to give their children one nitazoxanide 20-mg dispersible table every 12 hours for 3 consecutive days. Guardians of children aged 1 to 3 years were instructed to give their children 5 mL of a 100 mg/5 mL suspension every 12 hours for 3 consecutive days. No fasting was required, and the drug was to be administered with food. Based on negative findings on one posttreatment fecal examination performed 4 days after the end of treatment (study day 7), eradication rates of 81% (127 of 156), 95% (130 of 139), and 77% (10 of 13) were recorded for intestinal amebiasis, giardiasis, and balantidiasis, respectively. Nitazoxanide also showed good anthelmintic activity, with eradication rates of 95% (106 of 112), 95% (147 of 155), 96% (44 of 46), 86% (25 of 29), and 94% (34 of 36) for enterobiasis, ascariasis, ancylostomiasis caused by Ancylostoma duodenale, trichuriasis, and strongyloidiasis, respectively. Against the dwarf tapeworm, Hymenolepis nana, nitazoxanide therapy produced an eradiction rate of 85% (53 of 62). Nitazoxanide was well tolerated; 14.5% of the patients reported minimal side effects, such as nausea, headache, dizziness, vomiting, abdominal pain, and diarrhea. Hematolog, clinical chemistry, and urinalysis performed before and after treatment were unaffected by treatment with nitazoxanide. Key words: nitazoxanide, treatment, protozoa, helminths.

Prevalence of intestinal parasites in rural Southern Indians.

To determine the prevalence of intestinal protozoal and helminthic infection in a rural population. Seventy-eight members of 15 families from a village were studied. Stool samples from all subjects were examined on alternate days for one month. The overall prevalence rate of various parasitic infections was 97.4%, with only 2 of 78 subjects not excreting parasites in any of their 15 samples. Eighteen (23.1%) persons had only one type of parasite, while 58 (74.3%) excreted multiple parasites. Giardia and Cryptosporidium were the commonest protozoan infections, affecting 42/78 (53.8%) and 31/78 (39.7%), respectively. Hookworm infestations were the commonest helminthic infections, seen in 48/78 (61.5%). Based on excretion patterns, the asymptomatic individuals could be divided into 2 groups of infrequent and frequent excretors, indicating that the host response may determine the level of parasite replication in the gut.

Nitazoxanide for the treatment of intestinal protozoan and helminthic infections in Mexico

A study to evaluate the efficacy and safety of nitazoxanide as a single agent for the treatment of a broad spectrum of mixed parasitic infections, both protozoa and helminths, was conducted at a primary school in San Pedro Tolimán, Querétaro, Mexico. Three faecal samples from 1824 adults and children were screened for the presence of oocysts, cysts, trophozoites, eggs or larvae of intestinal protozoa or helminths. Two hundred and forty-six adults and children infected with at least one protozoan and 2 helminths were given 7·5 mg/kg of nitazoxanide (500 mg to adults and 200 mg to children less than 12 years old) every 12 h for 3 consecutive days. Faecal samples were examined on days 6, 7, 8, 13, 14 and 15 (±1) following initiation of treatment, using formalin-ether concentration and Kato-Katz egg counting. Treatment with nitazoxanide was 71–100% effective in eliminating evidence of infection with Entamoeba histolytica/E. dispar, Giardia duodenalis, Blastocystis hominis, Isospora belli, Enterobius vermicularis, Ascaris lumbricoides, Trichuris trichiura and Hymenolepis nana. Haematology and clinical chemistry values obtained before and after treatment remained unaffected by nitazoxanide. The drug was well tolerated, with only 15 patients (6·1%) reporting mild abdominal pain that lasted less than 24 h.