This article is a review of the latest information on the prevalence of G. lamblia in South Asia, South East Asia and Far East, characterizing the current endemic situation within these regions. Around 33 published papers from 2002-2007 were collected on G. lamblia. The included countries were Nepal, Bangladesh, India, Cambodia, Vietnam, Malaysia, Philippines, Indonesia, Thailand, Republic of Korea, and China. Only five published papers were discarded because data was extracted before 2002-2007 or they are not included within our regions, emphasizing more on G. lamblia in animals, or performed at extensive molecular level. The prevalence of G. lamblia varied markedly between studies illustrating higher levels in the urban than in the rural areas, more among poor communities, slightly higher in males than in females with age range of 2-5-year-old children, and among university students, old-aged people, HIV-positive patients, and gastric carcinoma patients. Though G. lamblia is not a life-threatening parasite, nevertheless, it is still considered as the most common water-borne diarrhea-causing disease. It is important to understand the etiology, frequency, and consequences of acute diarrhea in children. Routine surveillance such as bi-annual follow-up treatments, treating G. duodenalis cysts and other protozoa oocysts detected in ground water sources, and continuous health education are the most preventive measures.
Cryptosporidium and Giardia are major causes of diarrhoeal diseases of humans worldwide, and are included in the World Health Organisation's 'Neglected Diseases Initiative'. Cryptosporidium and Giardia occur commonly in Malaysian human and non-human populations, but their impact on disease, morbidity and cost of illness is not known. The commonness of contributions from human (STW effluents, indiscriminate defaecation) and non-human (calving, lambing, muck spreading, slurry spraying, pasturing/grazing of domestic animals, infected wild animals) hosts indicate that many Malaysian environments, particularly water and soil, are sufficiently contaminated to act as potential vehicles for the transmission of disease. To gain insight into the morbidity and mortality caused by human cryptosporidiosis and giardiasis, they should be included into differential diagnoses, and routine laboratory testing should be performed and (as for many infectious diseases) reported to a centralised public health agency. To understand transmission routes and the significance of environmental contamination better will require further multidisciplinary approaches and shared resources, including raising national perceptions of the parasitological quality of drinking water. Here, the detection of Cryptosporidium and Giardia should be an integral part of the water quality requirement. A multidisciplinary approach among public health professionals in the water industry and other relevant health- and environment-associated agencies is also required in order to determine the significance of Cryptosporidium and Giardia contamination of Malaysian drinking water. Lastly, adoption of validated methods to determine the species, genotype and subgenotype of Cryptosporidium and Giardia present in Malaysia will assist in developing effective risk assessment, management and communication models.
This study was conducted to reassess the risk factors for giardiasis in communities of the Orang Asli (indigenous people) in Pahang, Malaysia. Stool samples were collected from 321 individuals (2-76 years old; 160 males, 161 females). Data were collected via laboratory analysis of faecal samples and a pre-tested standard questionnaire. River water samples were tested for Giardia cysts and Cryptosporidium oocysts. The overall prevalence of G. intestinalis infection was 23.7%. Children < or =12 years old had the highest infection rate and have been identified as a high risk group (odds ratio (OR)=6.2, 95% CI 1.5-27.0, P<0.005). The risk of getting giardiasis also appeared to be significantly associated with drinking piped water (OR=5.1, 95% CI 0.06-0.7, P<0.005) and eating raw vegetables (OR=2.4, 95% CI 0.2-0.6, P<0.005). In conclusion, sociodemographic factors have always been associated with the high prevalence of Giardia infections in Malaysia. However, the present study also highlights the need to look into the possibility of other risks such as water and food transmission routes. In future, it is necessary that these two aspects be considered in control strategies.
Giardia duodenalis causes diarrhoea and malabsorption. The objectives of the study were to detect local isolates of G. doudenalis by polymerase chain reaction (PCR) and to determine their restriction fragment length polymorphisms (RFLP). G. doudenalis isolated from stools of patients from Hospital Orang Asli Gombak were cultured axenically using TYI-S-33 medium with 10% foetal calf serum. The commercially designed primer-pair 432/433 was used to amplify a 0.52 kb segment known to encode the homologous cysteine-rich trophozoite surface antigen (tsp11 and tsa417). Results showed that the primer-pair 432/433 could amplify the target region of the local isolates. RFLP study on the identical isolates showed that all the restriction enzymes tested ( HindIII, ClaI, PstI and Kpn) gave a banding pattern similar to that of the WB strain a reference pathogenic strain from human. The reference pathogenic strain were commercially obtained from the American Type Culture Collection (ATCC).
Cryptosporidium and Giardia are two important pathogenic parasites that have caused many waterborne outbreaks which affected hundreds of thousands of people. Contamination from effluent discharged by sewage treatment plants have been implicated in previous waterborne outbreaks of Cryptosporidium and Giardia. This study evaluated the reduction of Cryptosporidium and Giardia (oo)cysts in two sewage treatment plants (STPA and STPB) in Malaysia which employed different treatment processes for a period of a year. Raw sewage influents and treated sewage effluents were concentrated by repeated centrifugation, subjected to sucrose density flotation and concentrated to a minimal volume depending upon the levels of contaminating debris. Cryptosporidium oocysts and Giardia cysts were enumerated using epifluorescence microscopy. The parasite concentrations in raw sewage were 18-8480 of Giardia cysts/litre and 1-80 of Cryptosporidium oocysts/litre. In treated sewage, the concentration of parasites ranged from 1-1462 cysts/litre and 20-80 oocysts/ litre for Giardia and Cryptosporidium respectively. Statistical analysis showed that sewage treatment process which employed extended aeration could reduce the concentration of Cryptosporidium and Giardia (oo)cysts significantly but treatment process which encompasses aerated lagoon could only reduce the concentration of Giardia cysts but not Cryptosporidium oocysts significantly. This phenomenon is of great concern in areas whereby effluent of sewage treatment plants is discharged into the upstream of rivers that are eventually used for abstraction of drinking water. Therefore, it is important that wastewater treatment authorities rethink the relevance of Cryptosporidium and Giardia contamination levels in wastewater and watersheds and to develop countermeasures in wastewater treatment plants. Further epidemiological studies on the occurrence and removal of pathogenic organisms from excreta and sewage are also recommended, in order that the public health risks can be defined and the most cost effective sewage treatment options developed.
Giardia duodenalis is an intestinal parasite that causes diarrhoea and malabsorption in children. The parasite also infects AIDS patients with a weak immune system. A study was carried out on six local isolates of Giardia duodenalis (110, 7304, 6304, M007, 2002 and 6307) from faeces of Orang Asli patients admitted to the Gombak Hospital. WB, a reference pathogenic strain from human and G. muris from a wild mouse, were commercially obtained from the American Type Culture Collection (ATCC). All the isolates were cultured axenically in TYI-S-33 medium. Two sets of primers were used for the techniques: primers LP1 and RP1 and primers LP2 and RP2. The sets of primers amplified giardine gene of 171 bp and 218 bp in sizes respectively. The study showed that the two sets of primers could detect G. duodenalis to the genus and species level specifically.
A study to determine the contribution of Giardia cysts and Cryptosporidium oocysts from cattle farms was carried out at the Langat Basin. This study investigated the contribution of cattle farms, located near Sungai Langat and Sungai Semenyih, towards river contamination with these cysts and oocysts. The findings showed that out of 24 samples of water taken from Sungai Semenyih, 4.2% was positive for Giardia cysts with a concentration of 1.3 cysts/L and 20.8% were positive with Cryptosporidium oocysts with a range of 0.7 - 2.7 oocysts/L. At Sungai Langat, from the 43 samples taken, 23.3% were positive for Giardia cysts with a range of 1.5 - 9 cysts/L whereas 11.6% were positive with Cryptosporidium oocysts with a range of 2.5 - 240 oocysts/L. Isolation of cysts and oocysts in bovine faecal materials revealed that 14.6% of faecal samples were positive for Giardia cysts which had a range of 75 - 1.3x104 cysts/g and 25% were positive for Cryptosporidium oocysts with a range of 50 - 3.9x105 oocysts/g. From the cattle wastewater, 98% were positive with oocysts and 6.7% with cysts. The concentrations were between 20 - 3.1x103 oocysts/mL for Cryptosporidium and 4 - 75 cysts/mL for Giardia. Given that the prevalence of Cryptosporidium and Giardia are high amongst the cattle and the positive findings of the (oo)cysts in the river samples, it could be deduced that there is a very high possibility of the cattle farms contaminating the river with Giardia cysts and Cryptosporidium oocysts. Viability study of Cryptosporidium oocysts in the surrounding soil and pond within the cattle farm showed that the viability of Cryptosporidium oocysts decreased with time. It was estimated that it will take 52 days for all the oocysts from both environment to be non-viable. With a viability rate of approximately 2 months in a cattle farm setup, river water contaminated with Cryptosporidium oocysts has a high chance of acting as an agent of transmission. As cattle farms are also inhabited by the owners and their families, this problem may pose a threat to humans (e.g. children) especially if they are dependent on the river water as their source of water for their daily activities.
A total of 1,885 blood and stool samples of four main protozoan parasitic infections were retrospectively reviewed from January, 2000 to April, 2004. Eleven of the 1,350 stool samples were shown positive for Cryptosporidium and Giardia infections; one of the 5 cases was clinically diagnosed as gastrointestinal cryptosporidiosis, while 6 cases were giardiasis. In patients with giardiasis, children were among the high-risk groups, making up 66.7% of these patients. The common presenting signs and symptoms were: diarrhea (83.3%), loss of appetite (83.3%), lethargy (83.3%), fever (66.7%), nausea/vomiting (50.0%), abdominal pain (16.7%), dehydration (16.7%) and rigor and chills (16.7%). Metronidazole was the drug of choice and was given to all symptomatic patients (83.3%). For the blood samples, 28 of the 92 peripheral smears for Plasmodium spp infection were diagnosed as malaria. The age range was from 4 to 57, with a median of 32.5 years. The sex ratio (M:F) was 3.6:1, while the age group of 30-44 years was the most commonly affected in both sexes. The majority of patients were foreigners (60.7%) and non-professional (39%). Plasmodium vivax (71%) infection was the most common pathogen found in these patients, along with a history of traveling to an endemic area of malaria (31%). The predominant presenting signs and symptoms were: fever (27%), rigor and chills (24%), nausea/vomiting (15%) and headache (8%). Chloroquine and primaquine was the most common anti-malarial regimen used (78.6%) in these patients. The seroprevalence of toxoplasmosis in different groups was 258/443 (58%): seropositive for IgG 143 (32.3%); IgM 67 (15%); and IgG + IgM 48 (10.8%). The age range was from 1 to 85, with a mean of 34 (+/- SD 16.6) years. The predominant age group was 21 to 40 years (126; 28.4%). The sex ratio (M:F) was 1.2:1. Subjects were predominantly male (142; 32%) and the Malay (117; 26.4%). Of these, 32 cases were clinically diagnosed with ocular toxoplasmosis. The range of age was from 10 to 56 years with a mean of 30.5 (+/- SD 12.05) years. The sex ratio (M:F) was 1:1.7. The majority were in the age group of 21 to 40 years, female (20; 62.5%), and Malay (17; 53%). They were also single (16; 50%), unemployed (12; 37%), and resided outside Kuala Lumpur (21; 65.6%). The more common clinical presentations were blurring of vision (25; 78%), floaters (10; 31%) and pain in the eye (7; 22%). We found that funduscopic examination (100%) and seropositivity for anti-Toxoplasma antibodies (93.7%) were the main reasons for investigation. Choroidoretinitis was the most common clinical diagnosis (69%), while clindamycin was the most frequently used antimicrobial in all cases. Among HIV-infected patients, 10 cases were diagnosed as AIDS-related toxoplasmic encephalitis (TE) (9 were active and 1 had relapse TE). In addition, 1 case was confirmed as congenital toxoplasmosis.
A survey of the river water frequently used by the Temuan Orang Asli (aborigine) indicated that 66.7% of the river water samples were Giardia cyst positive and 5.6% were Cryptosporidium oocyst positive. Although Giardia cysts were detected in samples from all the sites (e.g. upstream, midstream, and downstream), Cryptosporidium was only present in one river water sample taken from downstream from a village. The only sample of upstream water which contained Giardia cysts had a concentration of 0.7 cysts/l. All samples taken from midstream contained cysts with a mean concentration of 9.8 +/- 6.6 cysts/l (range = 1-20 cysts/l). Eighty-three point three percent of the samples collected from downstream contained cysts and 16.7% had oocysts. The average concentration of cysts was 12.9 +/- 16.4 cysts/l (range = 0-44 cysts/l), whereas the oocyst concentration was 0.4 oocysts/l. All river samples tested positive for the presence of E. coli, indicating fecal contamination. The results of this study imply that the river system is contaminated with fecal-oral transmitted parasites. The river water, used by the Orang Asli, is a probable route for Giardia and Cryptosporidium transmission in this community. Long term strategies, incorporating health education regarding personal hygiene, and provision of toilets and the importance of their proper usage, need to be embraced by this community in order to control the spread of these parasites.
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.
A community study was carried out to evaluate the efficacy of a 3-day course of 400 mg albendazole daily in the treatment of Trichuris trichiura and Giardia intestinalis infection. This treatment regimen was effective in the treatment of Trichuris trichiura and Giardia intestinalis infection with cure rates of 91.5% and 96.6% respectively. Uses of a 3-day course of 400 mg albendazole daily should be considered in mass or targeted soil-transmitted helminths chemotherapy particularly in areas where the prevalence of Trichuris trichiura is high and polyparasitism is common.
One hundred seventy three stool samples were obtained from workers from Indonesia, Bangladesh, Myanmar, Pakistan and others. The stool samples were examined for Ascaris, Trichuris, Hookworm, Schistosomes, trematodes and cestodes. The protozaon parasites included Bnlantidiirrir coli, Blastocystis honlinis, Cyclospora cryptosporidium, Microsporidiirin, Entamoeeba histolytica, Giardia lamblia, lodamoeba butschilli. Of these 21.9%, 17% and 1% of the population studied had hookworm, Trichuris trichiura and Ascaris lumbricoides infections respectively. There was only one Indonesian reported to have Hymenolepis nana infections. The most common protozoan seen in the faecal sample is Blastocystis hominis (36%) followed by Giardia lamblia (4%). Most of the stools positive with these faecal pathogens were semisolid especially the ones positive for the protozoan. We have also shown Blastocystis from the Indonesian workers show very small forms almost 3-5 in size compared to the normal size of 10-15 pm in the other nationalities. These forms show a distinct growth profile in cultures and appears to be more resistant to temperature changes than Blastocystis seen in the other two nationalities. The high incidence of Hookworm and Trichuris infections is suggestive that if these workers are left unheated their productivity will be hampered by other possible serious complications such as anaemia, weight loss, abdominal pain with diarrhoea1 stools and nausea. There are increasing reports that Blastocystis hominis is pathogenic. Flatulence, abdominal discomfort and the increase in the frequency of the passing watery stool has been noted in patients infected with the parasite. Since most of the workers are generally housed in crowded rooms it is highly likely that this will facilitate transmission through the faecal-oral route of both Giardia and Blastocystis possibly increasing the incidences of these infections among workers.
A Giardia varani Lavier, 1923-like flagellate was found in the feces of a captive water monitor, Varanus salvator, originally caught wild from an unknown location in Malaysia. The parasite is similar in size and shape to Giardia lamblia, except that median bodies are rare and cysts are binucleate. A description of both the trophozoite and cyst stage of this flagellate is provided.
The total serum IgE levels in infants and children was quantitated by the radioimmunoassay technique. The serum levels increased from about 300 IUlml in the 2-3 month old infants to about 8000 1U/m1 in the 10-year-old children who were probably infected with intestinal helminths. The total serum IgE levels in infants with cow's milk protein-sensitive entero-pathy were similar in level to those in normal infants. Infants and children with acute gastroenteritis, giardia infection and malnutrition had elevated levels of serum IgE levels. The high serum I gE levels noted in Malaysian children are probably indicative of the pattern in the tropics. (Copied from article).