Trichuris Eggs Research Articles

Selective primary health care: strategies for control of disease in the developing world. XII. Ascariasis and trichuriasis.

Ascariasis and trichuriasis are the most prevalent and widespread intestinal helminthiases. Transmission of disease occurs by ingestion or inhalation of Ascaris and Trichuris eggs embryonated in the soil. During the migration of Ascaris to the lungs, pneumonic symptoms may develop. The intestinal stage of the parasite can cause severe symptoms and complications when the worm burden is high. High numbers of Trichuris may cause diarrhea. The poor standard of hygiene, the biology of the parasite (which is such that a high number of very resistant eggs are produced), and the habits of the host (such as the use of night soil) are factors causing a high prevalence of infection in many countries in Asia, Africa, South America, and Europe. The mechanism of the transmission of Ascaris varies in different communities. The peak of infection is among children aged four to 14 years. Worm burden is normally low, and only a small segment of the population harbors a high proportion of the worms present in a community. Control of infections due to Ascaris and Trichuris is feasible by a combination of mass chemotherapy with the effective drugs now available, safe disposal of excreta, destruction of the eggs, and health education.

Mebendazole in treatment of severe Trichuris trichiura infection in Malaysian children.

Children with severe Trichuris trichiura infection pose significant social, clinical, and therapeutic problems in Malaysia. Thirty such children were investigated, and mebendazole was found to be safe and effective in the treatment of severe trichuriasis but it had to be given for a longer period than currently recommended. A poor correlation was found between egg load and worm burden in these children. Direct visualization of the rectal and colonic mucosa was the most reliable method of assessing severity in untreated cases, and response to treatment. The eggs of Trichuris that had been exposed to mebendazole were morphologically altered and not viable when incubated. This may be of considerable epidemiological importance.

Therapeutic evaluation of oxantel pamoate (1, 4, 5, 6-tetrahydro-1-methyl-2-[trans-3-hydroxystyryl] pyrimidine pamoate) in severe Trichuris trichiura infection.

The efficacy of oxantel pamoate (1, 4, 5, 6-tetrahydro-2-[trans-3-hydroxystyryl]-1-methyl pyrimidine pamoate) was evaluated in 25 children with severe Trichuris infection. The presence of chronic dysentery and sigmoidoscopic demonstration of whipworms in the intestinal mucosa were the criteria for inclusion in the trial. Most of these patients had severe anemia, rectal prolapse, digital clubbing, hypoproteinemia, and growth retardation. There were a high incidence of concomitant parasitism with other intestinal helminths and with Entamoeba histolytica and Giardia lamblia. Sigmoidoscopic grading of Trichuris load and egg count in the feces were carried out prior to treatment and 2 days after each course of oxantel therapy. Oxantel was administered at a dose of 10 mg/kg body weight twice daily for a 3-day course. Satisfactory response, as judged by relief of dysentery and absence of whipworms from the mucosa at sigmoidoscopy, was achieved in 17 patients after the first course and in the remaining 8 patients after a second course of oxantel. The drug was well tolerated and no side effects were noted during or after treatment. It is concluded that oxantel is a safe and effective anthelmintic for severe clinical trichuriasis.

Development and Survival on Pasture of Gastrointestinal Nematode Parasites of Cattle

Development and survival of the larvae of gastrointestinal nematode parasites of cattle under nearly natural conditions were studied in 14 trials during 1960-64 at the Agricultural Research Center, Beltsville, Maryland. Fecal pats containing nematode eggs were deposited on pasture; at subsequent intervals, the pats and surrounding herbage were examined for larvae. Trials with Ostertagia ostertagi, Cooperia oncophora, and C. punctata were begun in spring, autumn, and winter, with Oesophagostomum radiatum in spring and winter, with Haemonchus contortus sensu lato in summer, and with Nematodirus helvetianus in spring. The average monthly temperatures for good development of Ostertagia larvae were 55 to 70.3 F, and for Cooperia and Oesophagostomum, 60.3 to 70.3 F. The monthly precipitations for good development of all three genera were 1.04 to 3.75 inches. The average monthly temperatures for good recovery of Ostertagia larvae from the herbage were 44 to 70.3 F, for Cooperia, 50.9 to 75.6 F, for Oesophagostomum, 69.8 F, and recovery of all three genera was maximal at 69.8 F. The monthly precipitations for good recovery of larvae from the herbage were 1.77-5.42 inches. Initial, peak, and final recoveries of infective larvae from the feces occurred 1.5 to 9 (avg 4), 1.5 to 23 (avg 6), and 1.5 to 26.5 (avg 14) weeks after deposition of the pats, respectively. Initial, peak, and final recoveries of infective larvae from the herbage occurred 1 to 11 (avg 5), 1.5 to 23 (avg 11), and 5 to 35 (avg 16) weeks after deposition of the pats, respectively. The ranges in periods of recovery were attributed primarily to differences between seasons. Summaries of some of our knowledge of factors affecting the development and survival of the free-living stages of gastrointestinal nematode parasites of ruminants on pasture are given by Lucker (1941), Kates (1950), Gordon (1957), Crofton (1963), and Levine (1963). In six trials at the Agricultural Research Center, Beltsville, Maryland (Goldberg and Rubin, 1956; Goldberg and Lucker, 1959, 1963), infectiousness of different pasture plots was determined in four to six tests per trial by grazing helminth-free calves on the plots at various intervals after contaminating them with feces containing worm eggs. The trials were begun in spring, summer, and autumn. The study of development and survival of larvae within feces, under natural conditions, has been very limited. Information on development and survival of larvae within the feces, as well as infectiousness of the herbage, was obtained in the autumn trials (Goldberg and Lucker, 1963) by examination of the feces and herbage for infective larvae at intervals after deposition of the feces. In the present study, development and survival of larvae in feces and infectiousness of herbage were studied by direct examination. The trials were Received for publication 31 May 1968. begun under a wider range of weather conditions than in the previous trials, and tests per trial were more numerous. MATERIALS AND METHODS Fourteen trials were conducted during 1960-64. Development and survival of Ostertagia ostertagi and Cooperia (C. oncophora and C. punctata) larvae were studied in 11 and nine of them, respectively, begun in spring, autumn, and winter. Oesophagostomum radiatum was studied in seven of them begun in spring and winter, Haemonchus contortus sensu lato in the three begun in July, and Nematodirus helvetianus in the one begun in May. A few Trichuris eggs were present in some trials. In 11 of the trials, the feces containing nematode eggs were obtained from naturally infected cattle; in three, feces were obtained from experimentally inoculated calves. Batches of feces were thoroughly mixed in an electric mixer and from 7 to 18 (avg 9) pats per batch were prepared. The pats were nearly hemispherical, approximately 11 cm in diameter and 5 cm high, and had the consistency of normal cattle feces. They weighed 300 g in 10 trials, 200 g in two, and 150 and 50 g in one each. In each trial, two pats were mixed with amounts of charcoal and water considered close to optimum for larval development and were cultured in the laboratory under approximately optimal ambient temperatures, except in summer when the ambient temperature was usually above optimum. The numbers of larvae recovered from these cultures provided an index of the potential for production of infective larvae by the eggs in the pats. These cultures are referred to hereinafter

Use of Thiabendazole-Medicated Feed for Prophylaxis of Four Common Roundworm Infections in Dogs

Use of Thiabendazole-Medicated Feed for Prophylaxis of Four Common Roundworm Infections in Dogs

Blood loss due to infection with Trichuris trichiura.

Fecal blood loss measured with Cyanomet-hemoglobin method was estimated in 9 children with various degrees of infection with Trichuris trichiura. The children ranged in age from 3-14 years. Stools were examined several times to rule out other parasitic infections. The eggs of only 1 other parasite Ascaris were found in 4 children. The red cell count packed red cell volume and hemoglobin were determined every 3-4 days. Serum iron and iron binding capacity were determined also. 6 of the 9 children had anemia with hemoglobin ranging from 4-11.2 g/100 ml of blood. The study children were passing in the stool from 1-14 million Trichuris eggs per day--4-118.7 thousand eggs per gram of feces. Expressing infection in terms of grams of feces gives only a very rough measure of burden since stools were watery in 6 cases. This means of expression was used because diarrhea is the most common symptom of the disease. Fecal blood loss ranged from 0.8-8.6 ml per day depending roughly on the degree of infection. It was reduced markedly after treatment except in case 3. This child expelled only 11 parasites and continued to pass over 1 million eggs daily. A high correlation was found between the net fecal blood loss and net number of eggs per day. There was no correlation between the fecal blood loss and the number of eggs per gram of feces because of the variable consistency of the feces. According to these results about 0.005 ml of blood is lost per day per each Trichuris which is 6-10 times less than from Necator americanus and 30-50 times less than from Ancylostoma duodenale. The amount of fecal blood loss per day per million eggs ranges from 0.21-1.58 ml with a mean of 0.78 ml. Approximately 0.25 ml of blood is lost per each 1000 eggs per gram of feces. It was estimated that infections of over 800 parasites producing over 5 million eggs daily induce anemia in children.

Action of aqueous solutions of iodine on fresh vegetables and on the infective stages of some common intestinal nematodes.

Summary Investigations were made on the concentrations of aqueous solutions of iodine required to kill the infective stages of Necator americanus, Ancylostoma caninum, Strongyloides stercoralis, Ascaris lumbricoides, Toxocara canis and Trichuris muris. Solutions containing 70 ppm free iodine, prepared by dissolving tablets of Globaline® or Heliogen® in distilled water, killed the infective free larvae of hookworms and Strongyloides within 5 minutes or less at temperatures ranging from 15°C to 30°C. To kill infective larvae in the eggs of Ascaris, Toxocara and Trichuris under similar conditions concentrations of 100, 120, and 250 ppm, respectively, were required. Killing action was more rapid at the low than at the high temperatures. Solutions at concentrations up to 500 ppm did not adversely affect the flavor or appearance of any of the common types of leafy or rooty vegetables. Solutions of sufficient strength to kill the eggs and larvae of these worms, and at the same time to destroy the common enteric microorganisms, are easily prepared and therefore appear to be suitable for the disinfection of vegetables to be consumed in the fresh state.

Effects of phthalofyne in the treatment of human Trichuris trichiura infection.

Summary Phthalofyne (3-methyl-1-pentyn-3-yl acid phthalate), a synthetic chemical compound demonstrated to have trichuricidal activity against both Trichuris vulpis and Trichuris trichiura, was given to 10 healthy young Filipino males harboring Trichuris trichiura. Of 7 cases who received 100 to 125 mg./kg. by mouth, alone or in combination with the same dose given by enema, 4 had rather minimal complaints of nausea and/or vomiting and none received significant therapeutic benefit. The highest oral dose, 175 mg./kg. given to a single patient, produced considerable nausea and apparently complete regurgitation of gastric contents and no therapeutic benefit, suggesting that effective single oral doses would not be easily retained. The phthalofyne enemas, containing respectively 200 mg./kg. and 450 mg./kg. of the drug, and given one week apart to a single patient, produced no side effects and no significant therapeutic effect. The simultaneous administration of 145 mg./kg. by mouth and 450 mg./kg. by enema resulted in moderately severe toxic effects including generalized malaise, nausea and vomiting, conjunctivitis, keratitis, and impaired auditory and visual acuity, all of which subsided within one to several days. In the one case so treated, Trichuris eggs were absent from the stools during a period of several days after therapy, though eggs were found in 1 of 3 stool specimens examined 6 weeks after therapy.

Comparative value of fecal examination procedures in the diagnosis of helminth infections

1. 1. Two groups of 250 stool samples each, proceeding from equal numbers of individuals, were collected at random in a known endemic focus of schistosomiasis mansoni and examined for eggs of Schistosoma and other helminths by the following procedures: direct saline smear (three 22 mm 2 preparations), HCl-triton-ether centrifugation, sodium sulfate-triton-ether centrifugation, HCl-sodium sulfate-triton-ether centrifugation, formalin-triton-ether centrifugation and sedimentation by gravity in glycerinated water. 2. 2. Both groups of samples were examined by the smear method and by HCl-triton-ether and sodium sulfate-triton-ether centrifugation. Sedimentation in glycerinated water was applied only to the first group of 250 stools; HCl-sodium sulfate-triton-ether and formalin-triton-ether centrifugation, only to the last group of 250 stools. 3. 3. Percentages of available cases diagnosed were determined on the basis of the total number of cases uncovered among each group of samples by the combination of methods applied. Average values of the number of eggs recovered by the concentration procedures were also calculated on the basis of the available cases. 4. 4. The percentage of available cases of schistosomiasis mansoni diagnosed, with the corresponding average number of eggs recovered, was as follows: three direct smears, 47%; HCl-triton-ether, 80%, 53; sodium-sulfate-triton-ether, 91%, 70; sedimentation in glycerinated water, 85%, 44; HCl-sodium sulfate-triton-ether, 76%, 45; formalin-triton-ether, 91%, 62. 5. 5. As respects the other helminth infections, the results may best be appreciated from the accompanying tables directly. 6. 6. The following conclusions may be derived from the data and observations: (a) Sodium sulfate-triton-ether and formalin-triton-ether proved the most effective concentration procedures for the detection of S. mansoni infections. Since they are so simply, cheaply and speedily performed, they appear to be the coprological methods of choice for survey or field work pertaining to this parasitosis. (b) Hydrochloric acid-triton-ether proved highly effective for the recovery of Trichuris and hookworm eggs, but decidedly unfavorable for the recovery of Ascaris eggs, infertile ones in particular, (c) Sodium sulfate-triton-ether proved highly effective for the recovery of Trichuris as well as S. mansoni eggs, but decidedly unfavorable as respects those of hookworm and Ascaris, infertile ones in particular. (d) Neither sedimentation in glycerinated water, as hereby executed, nor HCl-sodium sulfate-triton-ether proved outstanding in any respect, the latter behaving very much like HCl-triton-ether. (e) The direct saline smear proved superior to all the other methods for the detection of strongyloidiasis and, with the possible exception of glycerin water sedimentation, for the detection of fertile and infertile Ascaris infections. Its importance in other para-sitoses as a simple, rapid and efficient screening method before the application of concentration or noncoprological diagnostic procedures, or in distinguishing heavily from lightly infected individuals, is reaffirmed. (f) Of the concentration technics studied, formalin-triton-ether stands out as the nearest to an all-around diagnostic procedure, having proved highly effective in the detection of all the helminthiases here mentioned, with the exception of strongyloidiasis, and, on the basis of investigations made by others and incidental observations made by the present authors, of protozoan cysts as well.

Studies on the Rate of Development and Viability of the Eggs of Ascaris lumbricoides and Trichuris trichiura under Field Conditions

Most of the data on the rate of development and viability of the eggs of Ascaris lumbricoides and Trichuris trichiura have been obtained from the laboratory experiments in which the incubation and storage of the eggs were in aqueous media. Railliet (1893) found that at a favorable temperature Ascaris eggs contained motile embryos in 30 to 40 days. Davaine (1858) noted the formation of embryos in 30 days when Ascaris eggs were kept at a temperature of about 40? C. Likewise Leuckart (1876) found that in mid-summer the embryos are completely formed at the end of 40 days. More recently Wharton (1915) has reported that at summer temperatures in the Philippines Ascaris eggs develop completely in 15 days. From such data most workers conclude that in nature under the most favorable conditions of temperature and moisture the eggs of Ascaris take from 30 to 40 days to develop and those of Trichuris about twice as long. Likewise from the experiments of Davaine (1863), Morris (1911) and Epstein (1892) in which the eggs of Ascaris and Trichuris remained infective as long as five years in preserved feces it has been argued that eggs of these species probably remain viable and infective in nature a corresponding length of time. This opinion has been supported further by the results of experiments by Baillet (1866) and Cram (1924) who found Ascaris and Trichuris eggs to be very resistant to freezing temperatures. Ross (1916) reported that Ascaris eggs were still viable after having been exposed dry to the hot sun of India for as long a period as six weeks. Later workers on the other hand have found 98? C. lethal to