THE EFFECT OF MEDICATION ON QUESTIONNAIRE ANALYSIS OF CHILDREN WITH SCHISTOSOMA MANSONI INFECTION IN TANZANIA

The effect of mass treatment on questionnaire results in the diagnosis of schistosomiasis mansoni was examined in 267 school children in an endemic area of Tanzania by Kato-Katz analysis of fecal specimens. The questionnaire asked for information about self-diagnosis, abdominal symptoms, blood in stools, history of wild water contact, stool examination and medication for schistosomiasis, and knowledge of the disease. A logistic regression analysis disclosed a significant association between schistosomiasis and diarrhea (p ? 0.007; odds ratio, 32.0; confidence interval, 2.5 - 403.3) and abdominal enlargement (p ? 0.003; odds ratio, 15.2; confidence interval, 2.6 - 90.1) among 61 children who had no history of medication for schistosomiasis. The sensitivity and specificity of the model were 86% and 64%, respectively. In contrast, no significant correlation was observed either for the 116 treated children, or for all the 267 children after the mass treatment. We conclude, therefore, that for children who had no history of medication for schistosomiasis, the questionnaire for abdominal manifestations provides reliable information on S. mansoni infection. However, once a child takes medication, the questionnaire becomes unreliable. This observation suggests that immunomodulation by anti-schistosomiasis drugs that kill adult worms exerts an effect on the appearance of abdominal manifestations and might explain the ambiguity of clinical symptoms in chronically infested patients, except in terminal cases. Further studies are required to develop a simple, rapid and cost-effective diagnostic method for monitoring S. mansoni infection after medication in local areas without resort to laboratory-based identification of schistosomiasis

Variation in Thermal Stability among Respiratory Syncytial Virus Clinical Isolates under Non-Freezing Conditions

Virus isolates are not only useful for diagnosing infections, e.g., respiratory syncytial virus (RSV), but can also facilitate many aspects of practical viral studies such as analyses of antigenicity and the action mechanisms of antivirals, among others. We have been isolating RSV from clinical specimens from patients with respiratory symptoms every year since our first isolation of RSV in 1964, and isolation rates have varied considerably over the years. As collected clinical specimens are conventionally stored in a refrigerator from collection to inoculation into cells, we hypothesized that certain storage conditions or associated factors might account for these differences. Hence, we evaluated the thermal stability of a total of 64 viruses isolated from 1998 to 2018 upon storage at 4 °C and 20 °C for a defined duration. Interestingly, and contrary to our current understanding, 22 strains (34%) showed a greater loss of viability upon short-term storage at 4 °C than at 20 °C. Thirty-seven strains (57%) showed an almost equal loss, and only five strains (8%) were more stable at 4 °C than at 20 °C. This finding warrants reconsideration of the temperature for the temporary storage of clinical samples for RSV isolation

Low response in eliciting neuraminidase inhibition activity of sera among recipients of a split, monovalent pandemic influenza vaccine during the 2009 pandemic.

Antibodies against influenza virus neuraminidase (NA) protein prevent releasing of the virus from host cells and spreading of infection foci and are considered the 'second line of defence' against influenza. Haemagglutinin inhibition antibody-low responders (HI-LRs) are present among influenza split vaccine recipients. The NA inhibition (NAI) antibody response in vaccinees is worth exploring, especially those in the HI-LRs population. We collected pre- and post-vaccination sera from 61 recipients of an inactivated, monovalent, split vaccine against A/H1N1pdm09 and acute and convalescent sera from 49 unvaccinated patients naturally infected with the A/H1N1pdm09 virus during the 2009 influenza pandemic. All samples were subjected to haemagglutinin inhibition (HI), NAI and neutralisation assays. Most paired sera from naturally infected patients exhibited marked elevation in the NAI activity, and seroconversion rates (SCR) among HI-LRs and HI-responders (HI-Rs) were 60% and 87%, respectively; however, those from vaccinees displayed low increase in the NAI activity, and the SCR among HI-LRs and HI-Rs were 0% and 12%, respectively. In both HI-LRs and HI-Rs, vaccination with the inactivated, monovalent, split vaccine failed to elicit the NAI activity efficiently in the sera of the naive population, compared with the natural infection. Hence, the improvement of influenza vaccines is warranted to elicit not only HI but also NAI antibodies