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Background Ascaris lumbricoides is the most common causative agent of soil-transmitted helminth infections worldwide, with an estimated 450 million people infected with this nematode globally. It is suggested that helminths are capable of evading and manipulating the host immune system through the release of a spectrum of worm proteins which underpins their long-term survival in the host. We hypothesise that the worm overexpresses these proteins when infecting adults compared to children to cirvumvent the more robust defence mechanisms of adults. However, little is known about the parasite’s genes and encoded proteins involved during A. lumbricoides infection. Hence, this study was conducted to assess the expression profile of putative virulence-associated genes during an active infection of adults and children. Methods In this study, quantitative PCR was performed to evaluate the expression profile of putative virulence-associated genes in A. lumbricoides isolated from infected children and adults. The study was initiated by collecting adult worms expelled from adults and children following anthelminthic treatment. High-quality RNA was successfully extracted from each of six adult worms expelled by three adults and three children, respectively. Eleven putative homologues of helminth virulence-associated genes reported in previous studies were selected, primers were designed and specific amplicons of A. lumbricoides genes were noted. The expression profiles of these putative virulence-associated genes in A. lumbricoides from infected adults were compared to those in A. lumbricoides from infected children. Results The putative virulence-associated genes VENOM, CADHERIN and PEBP were significantly upregulated at 166-fold, 13-fold and fivefold, respectively, in adults compared to children. Conversely, the transcription of ABA-1 (fourfold), CATH-L (threefold) and INTEGRIN (twofold) was significantly suppressed in A. lumbricoides from infected adults. Conclusions On the basis of the expression profile of the putative virulence-associated genes, we propose that the encoded proteins have potential roles in evasion mechanisms, which could guide the development of therapeutic interventions. Graphical Abstract

Microsporidia are obligate intracellular parasitic fungi causing chronic diarrhea, particularly among immunocompromised patients. The current method used for diagnosis is based on conventional microscopy, which does not differentiate parasites at the species level. The present study was carried out to identify microsporidian species in immunocompromised patients. From March 2016 to March 2017, a total of 289 archived stool samples were examined microscopically for microsporidian spores using Gram-chromotrope Kinyoun (GCK) stain. Positive stool samples by microscopy were subjected to polymerase chain reaction and sequencing for species identification. Based on microscopy examination, the overall prevalence of microsporidian infections was 32.2% (93/289; 95% CI = 27.1-37.8). Of these stool samples, 45 samples were successfully amplified and confirmed as Enterocytozoon bieneusi. No Encephalitozoon intestinalis was detected. Accurate identification of species might help clinicians to decide appropriate management strategies as dissemination risks and treatment response vary for different species, hence improving the management of microsporidian infections.