Chikungunya fever is a viral disease transmitted by Aedes spp mosquitoes. The infection is endemic in parts of Africa, South-east Asia and on the Indian sub-continent.

The first outbreak of autochthonously transmitted Chikungunya virus (CHIKV) in Europe, which recently occurred in the province of Ravenna in north-eastern Italy has been completely controlled: the last case onset occurred on 28 September in the town of Rimini, and in October no cases were confirmed.

Dihydropteroate synthase gene of Plasmodium vivax was recently identified. In the present study, the sequences of the dyhydropteroate synthase gene of 68 P. vivax isolates from various geographic areas were compared. Sequencing revealed limited polymorphism at codons 383 and 553 in all analyzed samples. Interstrain analysis showed several genotypic variations in the tandem repeats domain which produce length polymorphism between different parasite isolates.

ABSTRACT A case of quinine-resistant Plasmodium falciparum malaria, followed by a postmalaria neurological syndrome and a recurrence episode, is described. Genetic characterization of the P. falciparum isolate obtained by analysis of msp1 and msp2 amplicons revealed the coexistence of two genotypes causing the first malaria episode and the presence of a unique isolate responsible for the recurrence.

Plasmodium vivax malaria was eradicated from Uzbekistan in 1961. Due to resurgence of the disease in neighbouring states and massive population migration, there has been an increase of P. vivax malaria, imported from Tajikistan, resulting in a number of indigenous cases being identified in areas bordering that country. A molecular study using the merozoite surface protein 1 (msp-1) gene as a marker was performed on 24 P. vivax genomic isolates from 12 indigenous and 10 imported malaria cases that occurred in the Surkhandarya region during the summer of 2002. Results have shown a significant difference in the frequency of msp-1 types between indigenous and imported isolates, the latter showing greater genetic heterogeneity. An entomological investigation in the area suggested that three Anopheles species, namely A. superpictus, A. pulcherrimus and A. hyrcanus may have a potential role in the endemic transmission of P. vivax.

The existing armamentarium of drugs for the treatment and prevention of malaria is limited primarily by resistance (and cross-resistance between closely related drugs). However, most of these drugs still have a place and their life-span could be prolonged if better deployed and used, and also by rationally combining them based on pharmacodynamic and pharmacokinetic properties. Newer compounds are also being developed. The nature of malaria disease and its prevalence in the developing world call for innovative approaches to develop new affordable drugs and to safeguard the available ones. According to WHO, the concept of combination therapy is based on the synergistic or additive potential of two or more drugs, to improve therapeutic efficacy and also delay the development of resistance to the individual components of the combination. Combination therapy (CT) with antimalarial drugs is the simultaneous use of two or more blood schizontocidal drugs with independent modes of action and different biochemical targets in the parasite. In the context of this definition, multiple-drug therapies that include a nonantimalarial drug to enhance the antimalarial effect of a blood schizontocidal drug are not considered combination therapy. Similarly, certain antimalarial drugs that fit the criteria of synergistic fixed-dose combinations are operationally considered as single products in that neither of the individual components would be given alone for anti-malarial therapy. An example is sulfadoxine-pyrimethamine. Artemisinin-based combination therapies have been shown to improve treatment efficacy and also contain drug resistance in South-East Asia. However, major challenges exist in the deployment and use of antimalarial drug combination therapies, particularly in Africa. These include: 1) the choice of drug combinations best suited for the different epidemiological situations; 2) the cost of combination therapy; 3) the timing of the introduction of combination therapy; 4) the operational obstacles to implementation, especially compliance. As a response to increasing levels of antimalarial resistance, the World Health Organization (WHO) recommends that all countries experiencing resistance to conventional monotherapies, such as chloroquine, amodiaquine or sulfadoxine/pyrimethamine, should use combination therapies, preferably those containing artemisinin derivatives (ACTs--artemisinin-based combination therapies) for malaria caused by Plasmodium falciparum. There is a promising role of such compounds in replacing or complementing current options. Since 1979, several different formulations of artemisinin and its derivatives have been produced and studied in China in several thousand patients for either P. falciparum or P. vivax malaria. To date, there is no evidence of drug resistance to these compounds. The use of artemisinin, artemether, arteether and artesunate for either uncomplicated or severe malaria is now spreading through almost all malarious areas of the world, although some of they have no patent protection, their development (with few exceptions) has not followed yet full international standards. Both artesunate, artemether and arteether are rapidly and extensively converted to their common bioactive metabolite, dihydroarte-misinin. WHO currently recommends the following therapeutic options: 1) artemether/lumefantrine; 2) artesunate plus amodiaquine; 3) artesunate plus sulfadoxine/pyrimethamine (in areas where SP efficacy remains high); 4) artesunate plus mefloquine (in areas with low to moderate transmission); and 5) amodiaquine plus sulfadoxine/pyrimethamine, in areas where efficacy of both amodiaquine and sulfadoxine/pyrimethamine remains high (mainly limited to countries in West Africa). This non artemisinin-based combination therapy is reserved as an interim option for countries, which, for whatever reason, are unable immediately to move to ACTs.

Chloroquine is a 9-aminoquinoline known since 1934. Apart from its well-known antimalarial effects, the drug has interesting biochemical properties that might be applied against some viral infections. Chloroquine exerts direct antiviral effects, inhibiting pH-dependent steps of the replication of several viruses including members of the flaviviruses, retroviruses, and coronaviruses. Its best-studied effects are those against HIV replication, which are being tested in clinical trials. Moreover, chloroquine has immunomodulatory effects, suppressing the production/release of tumour necrosis factor alpha and interleukin 6. which mediate the inflammatory complications of several viral diseases. We review the available information on the effects of chloroquine on viral infections, raising the question of whether this old drug may experience a revival in the clinical management of viral diseases such as AIDS and severe acute respiratory syndrome, which afflict mankind in the era of globalisation.

We observed an unusual case of Plasmodium vivax malaria who presented with an initial relapse four years after the primary infection. This occurred in Cameroon, where the patient, a 56-year-old priest, acquired a mild form of malaria and was treated with only chloroquine. Since he returned to Italy, he had not experienced any malaria-like symptoms, had not visited any other areas endemic for malaria, and had not received a blood transfusion. Blood smear microscopy confirmed the presence of Plasmodium spp . parasites, but unclear morphologic characteristics did not allow discrimination between P. vivax and P. ovale . A nested polymerase chain reaction-based molecular analysis identified P. vivax as the plasmodial species responsible. This case emphasizes the importance of taking into account the possibility of a very late initial relapse of P. vivax malaria and the relevant issues in terms of infection control.

Malaria transmission in the central highlands of Madagascar was interrupted in the 1960s by a national control program that used DDT indoor spraying and mass treatment with chloroquine. At the end of the 1980s in this region, epidemic malaria reappeared. Italian health authorities provided technical assistance to the National Malaria Control Program since the beginning of the resurgence of malaria in the central highlands. Yearly residual house spraying performed for 5 years (1993-1998) and the availability of antimalarial drugs reduced malaria transmission to very low levels, with improvement in parasitologic and entomologic indexes. A significant reduction of malaria prevalence was observed in the villages located at altitudes of 1,000-1,500 m, corresponding to the stratum of unstable malaria that was the main target of the antivector interventions. A significant reduction of malaria prevalence was also observed in the villages located at altitudes of 900-1,000 m, where malaria transmission is stable. The main vector Anopheles funestus was dramatically reduced in abundance and distribution in the sprayed areas.

Malaria due to Plasmodium vivax is globally widespread and is associated with substantial morbidity. The parasite was previously prevalent in temperate areas from which it has been eradicated, however there is a risk of re-introduction because of increased international travel and migration. Following the occurrence of an autochthonous case of P. vivax malaria in Italy after decades of malaria eradication, we applied a molecular approach to compare parasites involved in the introduced case and to determine whether a highly polymorphic gene marker could be useful to tag a P. vivax isolate geographically. To this end, the sequence encompassing the interspecies conserved blocks 5 and 6 of the gene encoding for merozoite surface protein 1 (msp-1) was determined in 16 P. vivax isolates from different regions, and analysed along with 24 pvmsp-1 sequences downloaded from published data. Results have shown that: (i) parasites from the introduced case and the putative source of infection identified following epidemiological investigation, although very similar, differed in three nucleotide substitutions, of which one non synonymous; ii) some geographical isolates looked tightly clustered (e.g. Korean and Punjab isolates), but others were less so.