Cryptosporidium parvum infections in a cohort of veterinary students in Sweden.

In March 2013, a veterinary student tested positive for Cryptosporidium; four classmates reported similar gastrointestinal symptoms. We aimed to identify source(s) and risk factors for Cryptosporidium infection in university persons symptomatic between 21 January and 14 April 2013. Sixty-four (79%) students from a cohort of 81 fourth-year veterinary students completed questionnaires, identifying 13 cases; four were Cryptosporidium parvum GP60 subtype IIaA16G1R1b, two were IIdA24G1, seven did not submit stool samples. Thirteen cases attended the university's field clinic before symptom onset (13/37 attendees, 35%); 11 visited at least one of four farms where students recalled seeing calves with diarrhoea. C. parvum subtype IIaA16G1R1b was identified in calves at one of the farms. Entering pens of calves with diarrhoea [relative risk (RR) 7·6, 95% confidence interval (CI) 1·7-33·5] and eating in clinic cars (RR 9·1, 95% CI 1·3-65·8) were associated with being a case. Washing hands at least twice per farm visit (0 cases, P = 0·03) was protective. This outbreak investigation was notable for rapid and effective collaboration between public health, veterinary and environmental sectors, leading to swift identification of a microbiological and epidemiological link between cases, infected calves and their farms. We recommend frequent hand-washing using proper technique and dissuasion from eating in clinic cars to minimize possible exposure to contaminated surfaces.

Evaluation of Toluidine Blue O staining for the diagnosis of Pneumocystis jiroveci in expectorated sputum sample and bronchoalveolar lavage from HIV-infected patients in a tertiary care referral center in Ethiopia.

BACKGROUND: Pneumocystis pneumonia (PCP) is becoming increasingly recognized in sub-Saharan Africa. The currently recommended diagnostic methods using induced sputum (IS) and bronchoalveolar lavage (BAL) are neither technically feasible nor affordable for a wider clinical use in developing countries. Therefore, there is a need for a simple and affordable diagnostic test. METHODS: The yield of Toluidine Blue O (TBO) stain, immunofluorescence (IF), and polymerase chain reaction (PCR) for the diagnosis of Pneumocystis jiroveci were compared in 78 expectorated sputum and 118 BAL samples of 131 HIV-infected patients presenting with atypical chest X-ray and sputum smear-negative for acid-fast bacilli. RESULTS: A total of 56 (42.7%) patients tested positive for P. jiroveci by PCR, 39 (29.4%) by IF, and 28 (21.4%) by TBO stain. The sensitivity of TBO as compared to IF and PCR was 71.4% and 34.5% in expectorated sputum and 68% and 41.5% in BAL samples, respectively, with a specificity approaching 100% in both. The sputum PCR showed high concordance rate with BAL PCR. The sensitivity and specificity of sputum PCR as compared to BALPCR was 78.9% and 89%, respectively. In both TBO and IF positive BAL samples, majority were from patients who could not produce sputum (p<0.001). The density of P. jiroveci clusters in BAL samples did not correlate with prior co-trimoxazole use, immunologic status of the patient or overall mortality. CONCLUSION: Compared to IF, TBO staining has an acceptable sensitivity and very high specificity both in expectorated sputum and BAL samples. Expectorated sputum is, therefore, the most practical specimen and TBO staining an inexpensive diagnostic method to be recommended for high-HIV, resource-constrained settings. Bronchoscopy for the diagnosis of PCP is often not required for patients who can produce sputum. For patients who cannot produce sputum, however, the cost and efficacy of TBO in IS sample needs to be investigated in resource-poor countries.

Antibody responses to a C-terminal fragment of the Plasmodium falciparum blood-stage antigen Pf332 in Senegalese individuals naturally primed to the parasite.

Previous studies have shown that antibodies from humans exposed continuously to malaria recognize the Plasmodium falciparum asexual blood-stage antigen Pf332. Here we analysed the antibody responses to a C-terminal fragment of Pf332, designated C231, in individuals from Senegal, by measuring the serum levels of immunoglobulin M (IgM), IgG class and subclass and IgE antibodies. IgG antibody reactivity with crude P. falciparum antigen was detected in all the donors, while many of the children lacked or had low levels of such antibodies against C231. The antibody levels increased significantly with age for both crude P. falciparum antigen and C231, and in the older age groups most of the donors displayed antibodies to C231. This was also true for IgM, IgE and IgG subclass reactivity against C231. Moreover, the ratio of IgG1/IgG2 was considerably lower for C231 than for crude P. falciparum antigen, and in age groups 10-14 and 15-19 years the levels of IgG2 against C231 even exceeded that of IgG1. The IgG2/IgG3 ratios suggest that C231 gives similar levels of IgG2 and IgG3, except for children aged 4-9 years, where IgG3 was higher. Raw IgM, IgG class and subclass and IgE antibody levels to C231 tended to be higher in those who did not experience a malaria attack, but following linear multivariate analysis the trends were not significant.