Assessment of in vitro sensitivity of Plasmodium vivax fresh isolates

Effectiveness of combined chloroquine and primaquine treatment in 14 days versus intermittent single dose regimen, in an open, non-randomized, clinical trial, to eliminate Plasmodium vivax in southern Mexico

Background

In Mexico, combined chloroquine (CQ) and primaquine (PQ) treatment has been used since the late 1950s to treat Plasmodium vivax infections. Although malaria transmission has declined, current treatment strategies must be evaluated to advance towards malaria elimination.

Methods

The clinical and parasitological outcome of treating symptomatic P. vivax with the 14-day (T14) treatment or intermittent single dose (ISD) regimen was evaluated in southern Mexico between February 2008 and September 2010. Patients over 12 months old with P. vivax mono-infection and asexual parasitaemia ≥500 parasites/µl were treated under supervision. After diagnosis (day 0), treatment began immediately. T14 patients received CQ for 3 days (10, 10 and 5 mg/kg) and PQ daily for 14 days (0.25 mg/kg), while ISD patients received a single dose of CQ (10 mg/kg) and PQ (0.75 mg/kg) on days 0, 30, 60, 180, 210, and 240. Follow-up was done by observing clinical and laboratory (by microscopy, serology and PCR) outcome, considering two endpoints: primary blood infection clearance and clinical response at ~28 days, and the incidence of recurrent blood infection during 12 months. Parasite genotypes of primary/recurrent blood infections were analysed.

Results

During the first 28 days, no differences in parasite clearance or clinical outcome were observed between T14 (86 patients) and ISD (67 patients). On day 3, 95 % of patients in both groups showed no blood parasites, and no recurrences were detected on days 7–28. Contrarily, the therapeutic effectiveness (absence of recurrent parasitaemia) was distinct for T14 versus ISD at 12 months: 83.7 versus 50 %, respectively (p = 0.000). Symptomatic and asymptomatic infections were recorded on days 31–352. Some parasite recurrences were detected by PCR and/or serological testing.

Conclusions

T14 was effective for opportune elimination of the primary blood infection and preventing relapse episodes. The first single dose of CQ-PQ eliminated primary blood infection as efficiently as the initial three-dose scheme of T14, but the ISD regimen should be abandoned. A single combined dose administered to symptomatic patients in remote areas while awaiting parasitological diagnosis may contribute to halting P. vivax transmission. Alternatives for meeting the challenge of T14 supervision are discussed.

Trial registration: NIH-USA, ClinicalTrial.gov Identifier: NCT02394197

Electronic supplementary material

The online version of this article (doi:10.1186/s12936-015-0938-2) contains supplementary material, which is available to authorized users.

Plasmodium vivax cerebral malaria complicated with venous sinus thrombosis in Colombia

Complicated malaria is usually due to Plasmodium falciparum. Nevertheless, Plasmodium vivax is infrequently related with life-threatening complications. Few cases have been reported of severe Plasmodium vivax infection, and most of them from Southeast Asia and India. We report the first case of cerebral malaria due to Plasmodium vivax in Latin America, complicated with sagittal sinus thrombosis and confirmed by a molecular method.

Genetic diversity of Plasmodium falciparum isolates from naturally infected children in north-central Nigeria using the merozoite surface protein-2 as molecular marker

OBJECTIVE

To characterize the genetic diversity of Plasmodium falciparum (P. falciparum) field isolates in children from Lafia, North-central Nigeria, using the highly polymorphic P. falciparum merozoite surface protein 2 (MSP-2) gene as molecular marker.

METHODS

Three hundred and twenty children were enrolled into the study between 2005 and 2006. These included 140 children who presented with uncomplicated malaria at the Dalhatu Araf Specialist Hospital, Lafia and another 180 children from the study area with asymptomatic infection. DNA was extracted from blood spot on filter paper and MSP-2 genes were genotyped using allele-specific nested PCR in order to analyze the genetic diversity of parasite isolates.

RESULTS

A total of 31 and 34 distinct MSP-2 alleles were identified in the asymptomatic and uncomplicated malaria groups respectively. No difference was found between the multiplicity of infection in the asymptomatic group and that of the uncomplicated malaria group (P>0.05). However, isolates of the FC27 allele type were dominant in the asymptomatic group whereas isolates of the 3D7 allele type were dominant in the uncomplicated malaria group.

CONCLUSIONS

This study showed a high genetic diversity of P. falciparum isolates in North-central Nigeria and is comparable to reports from similar areas with high malaria transmission intensity.

Effect of insulin on Blattela germanica Linnacus

OBJECTIVE

To determine the sensitivity of Blattela germanica L (B. germanica L) to differenct doses of insulin.

METHODS

B. germanica were reared in laboratory conditions at (25±2) °C and (50±5)% relative humidity (RH), and exposure period of 12:12 L/D. Different concentrations, viz. 5, 10, 15, 20 and 25 µ of insulin N, R, (N+R) were prepared and injected to 10 treated cockroaches with another 10 cockroaches which were injected with normal saline as control group.

RESULTS

Insulin N with a dose of 20 µ caused more than 70% mortality of B. germanica in this study. There was a significant difference between 20 µ of insulin N with other doses of 5, 10, 15 and 25 µ, and its comparison with other forms of medication also showed obvious difference (P<0.05).

CONCLUSIONS

It can be concluded that effective drug doses of insulin which can be used as posion bait or gel against German cockroaches could be utilized in the control of B. germanica in the future field studies.