Two quantitative trait loci influence whipworm (Trichuris trichiura) infection in a Nepalese population

BACKGROUND: Whipworm (Trichuris trichiura) infection is a soil-transmitted helminth infection that affects >1 billion people. It is a serious public health problem in many developing countries and can result in deficits in growth and cognitive development. In a follow-up study of significant heritability for whipworm infection, we conducted the first genome scan for quantitative trait loci (QTL) influencing the heritability of susceptibility to this important parasitic disease. METHODS: Whipworm egg counts were determined for 1,253 members of the Jirel population of eastern Nepal. All individuals in the study sample belonged to a single pedigree including >26,000 pairs of relatives that are informative for genetic analysis. RESULTS: Linkage analysis of genome scan data generated for the pedigree provided unambiguous evidence for 2 QTL influencing susceptibility to whipworm infection, one located on chromosome 9 (logarithm of the odds ratio [LOD] score, 3.35; genomewide P = .0138) and the other located on chromosome 18 (LOD score, 3.29; genomewide P = .0159). There was also suggestive evidence that 2 loci located on chromosomes 12 and 13 influenced whipworm infection. CONCLUSION: The results of this first genome scan for T. trichiura egg counts provides new information on the determinants of genetic predisposition to whipworm infection.     

Age-dependency of infection status and serum antibody levels in human whipworm (Trichuris trichiura) infection

This study examines the age-dependency of the relationships between human infection with whipworm (Trichuris trichiura) and parasite-specific antibody level measured by ELISA against an extract of adult worms after preincubation of the sera with Ascaris lumbricoides adult worm extract. The convex age-profile of parasite infection intensity is shown to be mirrored by an age-dependent change in age-class mean levels of IgG (all subclasses except IgG3), IgA, IgM and IgE. Mean antibody levels rise with increasing acquisition of infection in childhood and decline as the intensity of infection falls in adulthood. Immunoblot analysis of selected sera from different age-classes indicates that antigen recognition is similarly dependent on infection intensity. In individual children, antibody levels correlate positively with acquisition of infection, consistent with a simple model of antigen dosage specifying the magnitude of the humoral immune response. In adults, IgG4 correlates positively and IgA negatively with intensity of infection, suggesting involvement of these isotypes in functional roles of immune blockade or effector mechanisms, respectively.     

Humoral immune responses in human infection with the whipworm Trichuris trichiura

The humoral immune response to infection with Trichuris trichirua was investigated by ELISA and immunoblotting using human sera from the Caribbean island of St Lucia. Immunoblot analysis of the degree of cross-reactivity with the related trichuroid Trichinella spiralis and with the other commonly co-existent nematodes, Ascaris lumbricoides and Toxocara canis, was carried out using selected sera. The IgM, IgA, IgE, and IgG subclass antibody levels were measured in ELISA using a detergent solubilized extract of adult T. trichiura. The IgG and IgE responses were highly Trichuris specific. Anti-T. trichiura IgM responses were totally cross-reactive with A. lumbricoides and were completely ablated by pre-incubation of sera with Ascaris antigen. The IgG response was predominantly of the IgG1 subclass with a minimal IgG3 response. Only 1 person out of 130 tested had a detectable IgG3 response. The IgG2 response appeared to be directed primarily against carbohydrate or polysaccharide antigens as pre-treatment of the ELISA plates with poly-L-lysine was necessary before a response could be detected. These data are the first demonstration of human isotypic responses to infection with T. trichiura.     

Age-dependency of serum isotype responses and antigen recognition in human whipworm (Trichuris trichiura) infection

The present study examines the age-dependency of parasite-specific isotype responses and antigen recognition profiles of individuals within a Trichuris trichiura endemic community, in order to evaluate the significance of serum antibodies as determinants of observed age-related patterns of infection intensity. A high degree of individual heterogeneity is observed in isotype responses to separated T. trichiura antigens by Western blot. Recognition by IgG₁ antibodies exhibits marked age-dependency. The age-profiles of IgG₁ responses to selected antigens of 16–17 kDa and 90 kDa molecular weight reflect the age-related changes in current infection intensity at the population level. Similarly, mean age patterns of IgG₂ responses to a 90 kDa antigen, and mean IgG₄ responses to a 16–17 kDa antigen reflect mean infection levels. IgG₃ responses are negligible, and for methodological reasons, both IgE and IgM specificities are not presented. IgA responses to separated antigens of 16–17 kDa and 90 kDa, exhibit age-profiles which may suggest the development of an IgA-mediated acquired resistance to T. trichiura with age. IgA levels remain elevated throughout early adulthood, when infection intensity levels markedly decrease, supporting the hypothesis that IgA antibodies may be significant in generating the convex nature of the age-infection profile of T. trichiura.     

Effectiveness of mebendazole in Trichuris trichiura; a report on 2 cases of mild infection

Two admitted patients, a 5-year-old Filipino girl and a 29-year-old Indonesian man, who were diagnosed otherwise were concurrently found to harbour Trichuris trichiura eggs in stoll specimens containing 3,300 and 30 eggs per gram feces (EPG), respectively. A satisfactory response was obtained with administration of mebendazole in the recommended dose of 100 mg twice daily for three consecutive days. Repeated post-treatment fecal examinations revealed 0 EPG. Adverse reaction, either physical or laboratory, due to the anthelmintic was negative. The study indicates that the effectiveness of mebendazole on mild infection with T. trichiura is excellent without any untoward effect.     

Scanning electron microscopy of Trichuris trichiura (Nematoda)

Trichuris trichiura was examined in the scanning electron microscope and revealed a double row of sucker-like structures at the anterior part. It is postulated that they may support the attachment of the worm in host tissues. The sheath of the spicule is covered with spikes and the vulval opening is surrounded by an elevated rim-like structure with indentations.     

North American paragonimiasis: case report of a severe clinical infection

Paragonimiasis is an important cause of pulmonary disease worldwide. It results from an infection with Paragonimus, a parasite that reproduces through a complex life cycle involving snails, crustaceans, and mammals. Humans acquire the disease by ingesting uncooked freshwater crab or crayfish. Paragonimus species are distributed globally, and the disease is well known in endemic regions of Asia where culturally based methods of food preparation foster human transmission. Paragonimus also exists in regions of the United States but has been a rare cause of pulmonary disease. We report a case of a previously healthy young man who developed a dense empyema from Paragonimus kellicotti that ultimately required thoracotomy and praziquantel to eradicate his infection.     

A comparative trial of albendazole alone versus combination of albendazole and praziquantel for treatment of Trichuris trichiura infection

A randomized clinical trial was conducted to compare the effectiveness of albendazole alone and albendazole combined with praziquantel in the treatment of Trichuris trichiura infection. The drug regimens consisted of single dose of albendazole 400 mg (A1, n=34), 3 days of albendazole 400 mg daily (A3, n=34), 5 days of albendazole 400 mg daily (A5, n=35), single dose of albendazole 400 mg plus praziquantel 40 mg/kg (AIP1, n=34), and 3 days of albendazole 400 mg plus praziquantel 40 mg/kg daily (A3P3, n=36). It was found that treatment with 3 or more consecutive days of albendazole with or without praziquantel resulted in a significant reduction in density of Trichuris eggs in stools while a single dose of such drug did not. Praziquantel was not shown to have synergistic or antagonistic effects with albendazole. A regimen of 400 mg of albendazole daily for 3 days was found to be the most suitable therapy for Trichuris infection.     

The effectiveness of 3, 5 or 7 days of albendazole for the treatment of Trichuris trichiura infection

A randomized clinical trial was carried out to study the relationship between the duration of albendazole therapy, at 400 mg/day, and its effectiveness in the treatment of Trichuris trichiura infection. The 168 patients were treated for three (N=56), five (N=56) or seven (N=56) consecutive days. Compared with both of the shorter regimens, treatment for 7 days resulted in a significantly higher cure 'rate' and significantly greater reductions in the level of egg excretion. The advantage of using the longer (5- or 7-day) regimens was most apparent among the patients who had heavy infections (at least 1000 Trichuris eggs/g faeces) when treated. It is therefore suggested that albendazole be given for at least 3 days to those with light infections and for 5-7 days to patients with heavy infections.     

COVID-19 infection manifesting as a severe gastroparesis flare: A case report

Rationale:Coronavirus disease 2019 (COVID-19) is a disease caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which commonly presents with symptoms including fever, cough, and dyspnea. More recently, however, some patients have tested positive for COVID-19 after developing gastrointestinal (GI) symptoms either solely or in conjunction with respiratory symptoms. This may be due to SARS-CoV-2 infection of the GI tract. In patients with chronic GI illnesses, COVID-19 may initially present as a flare of their underlying GI conditions as viruses have historically been implicated in exacerbations of GI disorders, including gastroparesis.Patient concerns:We report a case of a 37-year-old female with a history of diabetic gastroparesis who presented to the Emergency Department (ED) with nausea and vomiting similar to her gastroparesis flares.Diagnoses:Her symptoms in the ED failed to improve with fluids and anti-emetic medications. After developing a fever, she was tested and found to be positive for COVID-19.Interventions:She was started on antibiotic, steroid, and antiviral medications.Outcomes:Her symptoms improved, her fever defervesced on day 4 of hospitalization, and she was discharged on day 5 of hospitalization. The patient reported symptom improvement at a follow-up outpatient gastroenterology visit 2 months after hospitalization.Lessons:To the best of our knowledge, at the present time, this is the first report of a patient with COVID-19 presenting with signs and symptoms of a gastroparesis flare. This case illustrates that COVID-19 may present in an exacerbation of symptoms of an underlying disorder, such as a severe gastroparesis flare, in a patient with underlying gastroparesis. Initial presentation of these patients manifesting as a flare of their chronic GI disease, more severe than usual, should prompt an index of suspicion for COVID-19.