Cellophane Thick Smear Research Articles

What was the main factor in successful control of ascariasis in Korea?

In the l950s, under the legacy of traditional agriculture, Ascaris lumbricoides, spread epidemically in the war-bitten society of Korea. Consensus on the parasite control was drafted in the Parasite Disease Prevention Act, which passed a parliamentary agreement in 1966, and established safe disposal of feces and mass chemotherapy as control strategies. Biannual stool examinations and treating infected schoolchildren were basic scheme of the control activity through which revenue could be secured for organized business. In the 27 years following 1969, a maximum of 16 million stool examinations had been done every year. Cellophane thick smear enabled the task. The infection declined remarkably in the 1970s when industrialization and green revolution proceeded. A population study of A. lumbricoides in the late 1970s helped us better understand its epidemiology. The data also settled down the understandable protest of teachers against the repeated stool examinations. In the 9 years following 1987, the target population was gradually reduced when the egg positive rate was below 0.1%. An article in the Korean Law, stipulating obligatory stool examinations, was made optional. Although the long-term Korean effort of Ascaris control was a success, the effect of mass chemotherapy was not as succinct in terms of lowering reinfection. In the period of control, Korean agricultural technology changed, and the economy grew and supplied sanitary facilities by which the vicious cycle was disconnected. Reduction of morbidity was a benefit of mass chemotherapy, which is the only control method feasible in economically difficult countries. The most important hurdle of parasite control in the 1960s was poverty of general population and limited financial resources in Korea but the society formed a consensus on the priority of intestinal helminthiasis control during the ordeal period. The national consensus in the 1960s was the critical milestone for Ascaris control in Korea. Under the social agreement, application of timely technical and research advancements in parasitology achieved the success of ascariasis elimination. The successful experience of ascariasis elimination in Korea can be a benchmark for countries where neglected tropical diseases are endemically recycled.

EVALUATION OF SOME MICROSCOPIC TECHNIQUES FOR DETECTING BILHARZIA AND INTESTINAL PARASITES

The objective of the present study was to evaluate the efficacy of five different diagnostic techniques (haematouria, macro-haematouria, syringe filtration, vacuum flask filtration and sedimentation) in the detection of urinary schistosomiasis. Likewise, five techniques (direct smear, cellophane thick smear, ether-formalin, modified Kato-template and modified Kato-syringe) techniques used in the detection of intestinal schistosomiasis and other intestinal parasites were evaluated using fecal samples. The results showed that the most efficient diagnostic technique for fecal samples is the modified Kato-Katz technique, while the ether-formalin method was the most sensitive tool for the detection of Schistosoma mansoni, Enterobius sp. and Ascaris sp. rates of infection and worm burden. The modified Kato techniques (template and syringe) failed to detect the intestinal protozoa, Giardia lamblia and Entamoeba histolytica, while the syringe filtration technique was the most powerful urine test.

Reduction of urogenital schistosomiasis with an integrated control project in Sudan.

PurposeSchistosomiasis remains a major public health concern in Sudan, particularly Schistosoma haematobium infection. This study presents the disease-reduction outcomes of an integrated control program for schistosomiasis in Al Jabalain locality of White Nile State, Sudan from 2009 through 2011.MethodsThe total population of the project sites was 482,902, and the major target group for intervention among them was 78,615 primary school students. For the cross-sectional study of the prevalence, urine and stool specimens were examined using the urine sedimentation method and the Kato cellophane thick smear method, respectively. To assess the impacts of health education for students and a drinking water supply facility at Al Hidaib village, questionnaire survey was done.ResultsThe overall prevalence for S. haematobium and S. mansoni at baseline was 28.5% and 0.4%, respectively. At follow-up survey after 6–9 months post-treatment, the prevalence of S. haematobium infection was reduced to 13.5% (95% CI = 0.331–0.462). A higher reduction in prevalence was observed among girls, those with moderately infected status (around 20%), and residents in rural areas, than among boys, those with high prevalence (>40%), and residents in urban areas. After health education, increased awareness about schistosomiasis was checked by questionnaire survey. Also, a drinking water facility was constructed at Al Hidaib village, where infection rate was reduced more compared to that in a neighboring village within the same unit. However, we found no significant change in the prevalence of S. mansoni infection between baseline and follow-up survey (95% CI = 0.933–6.891).ConclusionsAt the end of the project, the prevalence of S. haematobium infection was reduced by more than 50% in comparison with the baseline rate. Approximately 200,000 subjects had received either praziquantel therapy, health education, or supply of clean water. To consolidate the achievements of this project, the integrated intervention should be adapted continuously.

A Nationwide Survey on the Prevalence of Intestinal Parasitic Infections in the Republic of Korea, 2004

National surveys on the prevalence of intestinal parasitic infections have been carried out every 5-7 years since 1971 in the Republic of Korea in order to establish control measures. The present nationwide survey was conducted from June to December 2004. The 10% population sampling data of Population and Housing Census by the Korean government in 2000 was used as the survey population. One sample was selected randomly from each of the 22,858 registered subjects, and a total of 20,541 people were ultimately included in this survey. Fecal examinations were performed by the cellophane thick smear and saturated brine flotation techniques. Pinworm infection was examined by cello-tape anal swab method. This survey also included a questionnaire study for a socioeconomic analysis. The total helminth egg positive rate was 3.7%, and the estimated total positive number among nationwide people was 1,780,000. The rates in urban and rural areas were 3.1% and 6.8%, respectively. As the total egg positive rate in the 6th survey in 1997 was 2.4%, the present survey showed that there was a considerable degree of increase in the prevalence rate of intestinal parasitic infections over the 7-year period following the 6th survey. The largest increases occurred in the egg positive rates of Clonorchis sinensis and heterophyids including Metagonimus yokogawai.

Egg Laying Capacity of Haplorchis taichui (Digenea: Heterophyidae) in Humans

Quantitative fecal egg counts represented as the number of eggs per gram of feces (EPG) are generally a reliable parameter to estimate the worm burden of intestinal and hepatic parasitoses. Although Haplorchis taichui (Digenea: Heterophyidae) is one of the most common minute human intestinal flukes, little is known about the relationship between EPG and the actual worm burden in patients or the severity of the disease. In the present study, fecal samples were collected from 25 villagers in northern Thailand before and after praziquantel treatment. The EPG values of each participant were determined by the modified cellophane thick smear method, and adult worms were collected from the whole stool after the treatment. Eggs per day per worm (EPDPW) of H. taichui were estimated 82 from egg counts and expelled worms. The EPG was not well correlated with the worm burden, and a reverse correlation was observed between the EPDPW and the worm burden.

Pattern and predictors of soil-transmitted helminth reinfection among aboriginal schoolchildren in rural Peninsular Malaysia

Data on soil-transmitted helminth (STH) infections and reinfection among Orang Asli (aborigine) schoolchildren and their nutritional and socioeconomic status were analyzed to investigate the pattern and the possible predictors of STH reinfection. In this longitudinal study, 120 (60 males and 60 females) Orang Asli primary schoolchildren aged 7–12 years and living in remote areas in Pos Betau, Kuala Lipis, Pahang were screened for the presence of STH using modified cellophane thick smear and Harada Mori techniques. The overall prevalence of ascariasis, trichuriasis and hookworm infections were 65.8, 97.5 and 10.8%, respectively. After complete deworming with a 3-day course of 400 mg/daily of albendazole tablets, children were re-examined at 3 and 6 months from baseline. The reinfection rate, by one or more of STH species, at 3 months after deworming was high (49.5%) while 79.6% of the children were reinfected at 6 months after deworming. Logistic regression analyses showed that females, stunted children and those living in houses without toilets had significantly higher reinfection rates than others at 3 months ( P < 0.05). At 6 months, maternal employment status emerged as another predictor where children of working mothers had significantly higher reinfection rates ( P = 0.026). In conclusion, reinfection rate of STH is high and thus necessitates frequent and periodic deworming among children. Public health personnel need to re-look at the current control measures and identify innovative and integrated ways in order to reduce STH significantly in the rural communities.

Historical aspects for the control of soil-transmitted helminthiases

Japan has been one of the very few countries that operated the nationwide control programme against soil-transmitted helminths (STH) infections and gained a great success. On the basis of researches and operational studies, periodical mass-examination using cellophane thick smear (Kato technique) and selective mass-treatment targeted at school children were employed as the most useful control measure. In later years, Japan's experience and the strategy for STH control programme were transferred to Asian countries through Asian Parasite Control Organization (APCO) and also to countries of Asia, Africa and Latin-America through seminar at a modified form of the integration programme (IP) of STH control with family planning and nutritional improvement. The parasitologists group conducted studies in all aspects to seek effective STH control measures for respective countries and obtained many successful results.

Demographic and parasitic infection status of schoolchildren and sanitary conditions of schools in Sanliurfa, Turkey.

BackgroundThe design and development of school health programmes will require information at demographic characteristics of schoolchildren and the major health burdens of the school-age group, the opportunities for intervention and the appropriateness of the available infrastructure. This study aims to analyse demographic and parasitic infections status of schoolchildren and sanitary conditions of schools in Sanliurfa province of south-eastern Turkey.MethodThree primary schools were randomly selected in the shantytown, apartment and rural districts. A total of 1820 schoolchildren between 7–14 years age were took part to the survey of whom 1120 (61.5%) were boys and 700 (38.4%) were girls. A child form (including child's name, sex, age, school grade and parasitic infections) and school survey form (including condition of water supply, condition of latrines, presence of soaps on the basins and presence of garbage piles around to the schools) were used for demographic, parasitic and sanitary surveys. Stool samples were examined by cellophane thick smear technique for the eggs of intestinal helminths.ResultsThe demographic survey showed that number of schoolchildren was gradually decreased as their age's increase in shantytown school. The sex ratio was proportional until the second grade, after which the number of females gradually decreased in children in shantytown and rural schools while, in apartment area, schoolchildren was proportionally distributed between age groups and gender even the high-grade students. The prevalence of helminthic infections was %77.1 of the schoolchildren in shantytown, 53.2% in apartment district and 53.1% of rural area. Ascaris lumbricoides was the most prevalent species and followed by Trichuris trichiura, Hymenolepis nana and Taenia species in three schools. Sanitation survey indicated that the tap water was limited in shantytown school, toilet's sanitation was poor, available no soaps on lavatories and garbage piles were accumulated around the schools in shantytown and rural area, while, the school in apartment area was well sanitised.ConclusionsThese results indicated that burden of parasitic infections and poor sanitation conditions constituted public health importance among to the shantytown schoolchildren. School health programmes including deworming and sanitation activities through the health education and improvement of sanitation conditions in the schools have a potential to better health and education for schoolchildren. These programmes also offer the potential to reach significant numbers of population in the shantytown schools with high level of absenteeism.

Prevalence of intestinal parasite infections on a national scale among primary schoolchildren in Laos.

In order to investigate the epidemiological situation of intestinal parasite infections in Laos, parasitological surveys were carried out on a national scale including 17 provinces and the Vientiane Municipality. A total of 29,846 stool specimens were collected from primary schoolchildren from May 2000 to June 2002 and examined once with the cellophane thick smear technique. The cumulative egg positive rate for intestinal helminths was 61.9%. By species, the rate for Ascaris lumbricoides was 34.9%, hookworm 19.1%, Trichuris trichiura 25.8%, Opisthorchis viverrini 10.9%, Taenia spp. 0.6% and Hymenolepis spp. 0.2%. The northern mountainous regions such as Phongsaly, Huaphan or Saysomboune Province showed a higher prevalence (over 70%) of soil- transmitted helminths. The regions along the Mekong River such as Khammuane, Saravane or Savannakhet Province showed a higher prevalence (over 20%) of fish-borne parasites. On the other hand, Schistosoma mansoni eggs were detected in 1.7% of schoolchildren only in Champassak Province, a previously endemic area. The highest prevalence was noted in Phongsaly Province (96.0%) and the lowest in Bolikhamxay Province (27.5%). An additional small-scale survey by cellophane anal swab detected Enterobius vermicularis eggs in 35.7% of 451 schoolchildren aged 6-8 years in Khammuane, Vientiane, Champassak Province and the Vientiane Municipality. Meanwhile, the mean blood haemoglobin level of hookworm-infected children was not lower than that of children not infected with hookworm, suggesting that nutritional factors are more important than parasite infection per se. Nevertheless, the above results indicate that a nationwide parasite control project is necessary to reduce possible morbidity due to parasitic diseases in the country.

Epidemiological study of clonorchiasis and metagonimiasis along the Geum-gang (River) in Okcheon-gun (County), Korea

The endemic status of clonorchiasis and metagonimiasis along the Geum-gang (River) in Okcheon-gun (County) in Korea was examined. From February to December 2000, stools of total 1,081 inhabitants living in 5 villages were examined. Each stool specimen was examined by both the cellophane thick smear method and the formalin-ether sedimentation technique. Egg-positive cases were further analyzed by Stoll's egg-counting technique, and praziquantel was administered to positive cases. The egg-positive rates for Clonorchis sinensis and Metagonimus species were 9.3% and 5.5%, respectively, and the double infection rate was 3.5%. The numbers of eggs per gram (EPG) of feces of C. sinensis and Metagonimus sp. were 918 +/- 1,463 and 711 +/- 947, respectively. The egg-positive rates for C. sinensis and Metagonimus sp. in the riverside area were 14.2% and 8.4%, respectively, which were significantly higher than those of the inland area (3.2% and 1.7%, respectively). The egg-positive rates of C. sinensis and Metagonimus sp. in males (16.7% and 10.0%) were significantly higher than those of females (3.5% and 1.8%). However, there were no significant differences of EPG values between localities and sexes. The prevalence of clonorchiasis and metagonimiasis in this survey was significantly lower than that in the previous reports. However, there is still a high prevalence of infection with C. sinensis and Metagonimus sp. in this region, especially in the riverside area.

High endemicity of Metagonimus yokogawai infection among residents of Samchok-shi, Kangwon-do.

A small-scale epidemiological survey was undertaken during 1997-1998 on the residents along the Osib-chon (Stream), Samchok-shi (City), Kangwon-do (Province), to evaluate the status of Metagonimus yokogawai infection. A total of 165 fecal samples was collected and examined by cellophane thick smear and formalin-ether sedimentation techniques. The egg positive rate of M. yokogawai was 29.7%, showing a remarkable difference between males (46.6%) and females (16.3%). To obtain the adult flukes of M. yokogawai, 11 egg positive persons were treated with praziquantel and purged with magnesium sulfate. A total of 242,119 adult flukes (average 22,010 per person, 367-119,650 in range) was collected from diarrheic stools, all of which were identified as M. yokogawai. The results show that M. yokogawai is still highly endemic in this area.

Two endemic foci of heterophyids and other intestinal fluke infections in southern and western coastal areas in Korea.

Two endemic foci of heterophyid infections were discovered in coastal villages of Puan-gun, Chollabuk-do, and Sachon-gun. Kyongsangnam-do, Korea. Fecal examinations were performed on 153 inhabitants of Puan-gun and 138 of Sachon-gun, using cellophane thick smear and formalin-ether sedimentation technique. The helminth egg and/or protozoan cyst positive rate was 21.5% (33/153) in Puan-gun and 39.1% (54/138) in Sachon-gun. In Puan-gun, the egg positive rate of heterophyids was the highest, 17.6%, and that of other parasites was 0.7-2.6% by parasite species. In Sachon-gun, that of heterophyids was 18.8%, followed by Clonorchis sinensis (12.3%), and other parasites (0.7-5.0%). Twenth-two (Puan-gun) and six (Sachon-gun) heterophyid egg positive cases were treated with praziquantel, and adult flukes were collected from their diarrheic stools. A total of 3,284 adult flukes of Heterophyes nocens was collected from all of the 22 patients treated in Puan-gun (3-778 individually), and other trematodes were also collected from 2-15 patients: Pygidiopsis summa, Stellantchasmus falcalus. Metagonimus yokogawai, M. miyatai, Stictodora fuscata. Heterophyopsis continua, Acanthoparyphium kurogamo, and Gymnophalloides seoi. In Sachon-gun, M. yokogawai (3,007 specimens), H. nocens (120), and S. falcatus (46) were collected from 5 of 6 treated patients, and H. continua and S. lari each from one patient. The present study revealed that heterophyid flukes, especially H. nocens and M. yokogawai, are prevalent in the southern and western coastal areas of Korea where fresh and/or brackish water fishes are popularly eaten raw.

The first discovery of an endemic focus of Heterophyes nocens (Heterophyidae) infection in Korea.

A highly endemic focus of human infection with Heterophyes nocens (Heterophyidae) was discovered from a small coastal village of Shinan-gun, Chollanam-do, for the first time in Korea. Fecal examinations by cellophane thick smear and formalin-ether sedimentation techniques revealed 42.9% heterophyid egg positive rate out of 98 inhabitants examined. It was difficult to confirm the species of heterophyids only by eggs. In order to collect the adult flukes, the egg positive cases were treated with 10 mg/kg single dose of praziquantel and purged with magnesium sulfate, and the adult worms were collected from the diarrheic stools. From each of 18 cooperative patients 1 to 1,124 (total 4,730) H. nocens worms were recovered, together with a few to large numbers of heterophyids (Pygidiopsis summa, Stictodora fuscatum) and/or gymnophallids (Gymnophalloides seoi). It is speculated that H. nocens might be widely distributed along the southwestern coastal areas where the brackish water fish such as the mullets or gobies are popularly eaten raw.

Intestinal parasite and Clonorchis sinensis infection among the inhabitants in the upper stream of Taechong Dam, Kumgang (River)

The prevalence of intestinal parasites and Clonorchis sinensis infection was observed among inhabitants in the upper stream of Kumgang (River) from January to October 1991. A total of 743 fecal specimens was examined by cellophane thick smear and formalin-ether concentration technique. The parasite positive rate including helminth eggs and protozoan cysts was 40.8%, the positive rates for every species were: Clonorchis sinensis 30.8%, Metagonimus spp. 14.5%, Fasciola spp. 0.7%, Taenia spp. 1.5%, Ascaris lumbricoides 0.4%, Enterobius vermicularis 0.1%, Hookworm 0.1%, Trichuris trichiura 1.6%, Entamoeba coli 0.7%, E. histolytica 0.3%, Endolimax nana 0.3%, Giardia lamblia 0.3% and Iodamoeba buetschlii 0.1%, respectively. The cumulative positive rate in Okchon-gun showed 51.1%, in the Kumsan-gun 50.8% and in the Muju-gun 28.6%. Through this survey, it was concluded that the soil transmitted intestinal parasites including helminthseggs and protozoan cysts have been decreased remarkably among the inhabitants along the upper stream of Taechong Dam, Kum-gang (River), on the other side, Clonorchis sinensis, Metagonimus spp. and Taenia spp. are still morderate prevalent.

Intestinal parasite infections in the inhabitants along the Hantan River, Chorwon-gun.

The prevalence of intestinal parasite infections in inhabitants at the reaches of the Hantan River, Chorwon-gun, Korea, was observed from August 12 to September 14, 1993. Of 465 people observed by cellophane thick smear and formalin-ether concentration method, 2 Ascaris lumbricoides (unfertilized), 1 Trichuris trichiura, 39 Clonorchis sinensis and 16 Metagonimus egg positive cases were found. After treatment, the Metagonimus egg positive cases passed out flukes of Metagonimus Miyata type. Of 68 fish caught in the Hantan River, 14 (20.6%) were infected with metacercariae of Metagonimus, while no metacercaria of C. sinensis was found. At this area, soil-transmitted nematodes are very low, but clonorchiasis and metagonimiasis are prevalent by modernate endemicity.

Comparative study on the effectiveness of modified Kato's cellophane thick smear and Stoll's dilution egg counting technique for quantitative fecal examination of helminth eggs

A total of 197 fecal specimens was prepared for quantitative examination of helminth eggs by modified Kato's cellophane thick smear (M.C.T.S.) and Stoll's dilution egg counting technique (D.E.C.T.). The comparative effectiveness of two techniques was evaluated and conversion function was deduced. The average time required for the microscopic examination on one slide by M.C.T.S. was 12.6 minutes and that of D.E.C.T. was 14.6 minutes. M.C.T.S. showed lower false negative rate than D.E.C.T. in light worm burden cases. Functions to convert the counts obtained by M.C.T.S. to E.P.G. by Stoll's dilution egg counting technique were 47.86 x 10(0.87) logM.C.T.S. in A. lumbricoides, 41.69 x 10(0.82) logM.C.T.S. in T. trichiura and 63.10 x 10(0.85) logM.C.T.S. in C. sinensis. It was suggested M.C.T.S. be better than D.E.C.T. for the quantitative examination of intestinal helminthiases such as A. lumbricoides, T. trichiura, and C. sinensis infections even in the cases with low worm burden.

Albendazole treatment in human taeniasis

The results are presented of albendazole trials on human taeniasis infections in Honduras, involving 56 of 68 individuals (2% of the inhabitants) found to be infected during surveys conducted in 15 rural communities. Of the 3 methods used for diagnosis of infection, the Kato cellophane thick smear showed 80% reliability, a combination of Kato and ‘Scotch’ tape perianal swab 88%, and clinical history of proglottid expulsion less than 50%. Individuals were treated with a dose of 400 mg of albendazole per day for 3 d, followed for 5 d to verify tapeworm expulsion, and evaluated again at 60 and 90 d to assess drug efficacy. All 56 treated individuals remained stool-negative after 60 and 90 d; a partial strobila or segments were recovered from 21 of them (37·5%). Of these, Taenia saginata was identified from 4, and T. solium from 15; 2 specimens could not be specifically identified. Based on negative stool examinations and clinical history after 60 and 90 d, albendazole seems to be a well tolerated, very effective drug for treating infections with Taenia spp. However, confirmation of these results is needed due to the difficulty of making a reliable diagnosis of such infections.

Intestinal parasite infections among inhabitants in two islands of Tongyeong-gun, Kyeongsangnam-do

This study was performed to evaluate the status of intestinal parasitic infections among the inhabitants in two islands (Chu-do and Doomi-do) of Tongyeong-gun, Kyeongsangnam-do (Province), from August to September, 1989. A total of 189 stool specimens was collected from the inhabitants of 3 villages and examined by Kato's cellophane thick smear and formalin-ether sedimentation techniques. Stoll's dilution egg counting technique was done for the quantitative examination of helminth eggs. The overall positive rate of intestinal parasites was 30.2%. The egg positive rate of Ascaris lumbricoides was 2.1%, that of Trichuris trichiura 24.3%, hookworm 2.1%, Trichostrongylus orientalis 0.5%, Clonorchis sinensis 1.1%, heterophyid 1.6%, and Taenia species 2.6%. The cyst positive rate of Giardia lamblia was 1.6% and that of Entamoeba coli 0.5%. In T. trichiura infection, the egg positive rate of females (29.9%) was much higher than that of males (17.2%). Among the age groups, 10-19 year group showed the highest infection rate, 32.4%. It was revealed that the prevalence of intestinal parasitic infections among the inhibitants of remote islands should be still high in comparison with ever-reported ones in urban or rural areas.

Status of intestinal parasite infections in inhabitants of Palmar, Guayas Province, Ecuador

Status of intestinal protozoan and helminthic infections was surveyed in mestizo population living in rural parish of Palmar and its nearby recintos(villages). Three of the surveyed villages were at the Pacific coast and 5 villages were in inner pasture land, located about 100 km west of Guayaquil, the second largest city in Ecuador. One stool sample was examined by one cellophane thick smear for helminth ova and one direct smear stained with Lugol's iodine solution for protozoan cysts. Of 325 persons examined, 66.1% were positive for any ova or cyst. The positive rates were: 18.1% for Ascaris lumbricoides, 19.4% for Trichuris trichiura, 0.6% for hookworm, 3.7% for Hymenolepsis nana, 1.8% for Taenia sp., 19.4% for Entamoeba histolytica, 28.6% for Entamoeba coli, 5.5% for Endolimax nana, 1.5% for Iodamoeba buetschlii, 11.1% for Giardia lamblia and 0.6% for Chilomastix mesnili. Poor supply of potable water was considered the main cause of high prevalence of intestinal protozoan infections.

Diagnostic Value of the Intradermal Test for the Infection with Clonorchis sinensis

The intradermal(ID) test has been widely used in Korea and several reports about the results of the ID test are known. We examined the egg of Clonorchis sinensis(C. s.) by ID test in 443, stool's egg-counting technique in 79 and direct smear(cellophane thick smear technique) in 1304 subjects. The results are as follows.: 1. The positive rate of C. s. was 3.8% out of 1304 persons. 2. The sensitivity of ID test was 82.1% out of 39 persons and, the specificity was 64.6% out of 404 persons. 3. The false positive of ID test 35.4% out of 404 persons and, the false negative was 17.9% out of 39 persons. Intradermal test is a rapid, sensitive and useful supplementary diagnostic tool for the detection of Clonorchiasis infection and must be used as screening test with direct smear of stool but cross reaction with other helminth infections and moderate false reaction are the main disadvantages in its practical application.