GloPID-R report on Chikungunya, O'nyong-nyong and Mayaro virus, part I: Biological diagnostics.

The GloPID-R (Global Research Collaboration for Infectious Disease Preparedness) Chikungunya (CHIKV), O'nyong-nyong (ONNV) and Mayaro virus (MAYV) Working Group is investigating the natural history, epidemiology and medical management of infection by these viruses, to identify knowledge gaps and to propose recommendations for direct future investigations and rectification measures. Here, we present the first report dedicated to diagnostic aspects of CHIKV, ONNV and MAYV. Regarding diagnosis of the disease at the acute phase, molecular assays previously described for the three viruses require further evaluation, standardized protocols and the availability of international standards representing the genetic diversity of the viruses. Detection of specific IgM would benefit from further investigations to clarify the extent of cross-reactivity among the three viruses, the sensitivity of the assays, and the possible interfering role of cryoglobulinaemia. Implementation of reference panels and external quality assessments for both molecular and serological assays is necessary. Regarding sero-epidemiological studies, there is no reported high-throughput assay that can distinguish among these different viruses in areas of potential co-circulation. New specific tools and/or improved standardized protocols are needed to enable large-scale epidemiological studies of public health relevance to be performed. Considering the high risk of future CHIKV, MAYV and ONNV outbreaks, the Working Group recommends that a major investigation should be initiated to fill the existing diagnostic gaps.

CYP2C9 genotypes and the quality of anticoagulation control with warfarin therapy among Brazilian patients.

OBJECTIVE: To evaluate the impact of the two most common CYP2C9 variant alleles (*2 and *3) on the maintenance dose of warfarin and on the quality of anticoagulation control in Brazilians. METHODS: Patients (n = 103) initiated warfarin therapy with 5 mg/day (or 2.5 mg/day when over 80 years old). The international normalized ratio (INR) was targeted between 2 and 3, monitored every week until four consecutive adequate measures had been obtained, and then monthly. Serious hemorrhagic events were defined by the need for inpatient hospitalization. CYP2C9 genotyping was obtained by PCR-RFLP. RESULTS: The frequencies of CYP2C9*2 and CYP2C9*3 were 0.097 and 0.073, respectively, with genotypic distribution fitting Hardy-Weinberg equilibrium. CYP2C9 genotype was the only clinical feature associated with the risk of severe bleeding (one-sided P = 0.019, Fisher exact method), with an odds ratio of 4.8 (95% confidence interval of 1.4-16.6) for any variant genotype as compared to CYP2C9*1*1. Patients with either CYP2C9*2 or CYP2C9*3 were equally difficult to maintain in the INR target range, showing significantly (one-sided P = 0.038, Mann-Whitney U-test) reduced ratio of adequate INR measures (0.54 +/- 0.2), when compared to CYP2C9*1*1 patients (0.63 +/- 0.2). Patients with CYP2C9*3, but not CYP2C9*2, required significantly (one-sided P = 0.001, Mann-Whitney U-test) lower warfarin maintenance doses (3.1 +/- 1.8 mg) than CYP2C9*1*1 patients (5.3 +/- 2.1 mg). CONCLUSION: Patients with either CYP2C9*2 or CYP2C9*3 show higher risk of over-anticoagulation compared to CYP2C9*1*1 subjects and could benefit from a reduction in the initial warfarin standard dose (e.g., to 2.5 mg/day).

Dietary iron supplementation does not aggravate experimental malaria in young rats.

The hypotheses that iron-deficient hosts are less susceptible to severe malaria and that iron supplementation aggravates infection have been supported by some clinical and experimental evidence. In the present study, the course of Plasmodium berghei infection was monitored in an experimental model of dietary iron deficiency and iron supplementation. Weanling Wistar rats were fed purified diets with different iron concentrations: 20 mg/kg (Group D, n = 24), 50 mg/kg (Group N, n = 24) and 100 mg/kg (Group S, n = 12). After 15 d, rats from Group D were anemic (mean hemoglobin 81 g/l). The next day, 12 rats from Group D (thereafter Group DS) and 12 rats from Group N (thereafter Group NS) were transferred to the same iron-supplemented diet as in Group S, whereas the remaining animals (Groups D, N and S) were maintained on the original diets for further 14 d. At that time, 9 rats from each group were inoculated intraperitoneally with 10(6) erythrocytic parasites (P. berghei ANKA strain), whereas 3 rats from each group remained as noninfected controls. All animals were killed 14 d after inoculation, when significantly lower levels of hemoglobin, serum iron and percent transferrin saturation were found in infected animals from Group D compared with all other groups. However, the time course of parasitemias was similar in all groups. These data indicate that the development of P. berghei was neither suppressed by iron deficiency nor enhanced by iron supplementation in this model. Furthermore, iron repletion during infection did produce a noticeable improvement of hematological variables in previously iron-deficient animals.