Imported malaria in Italy from 1986 to 1988.

The trend of imported malaria cases in Italy from 1960 to 1988 is discussed. Comparative analysis of malaria incidence in the last three years is also presented. Since 1985, a rapid increase was recorded with 191 cases in 1986, 287 in 1987 and 350 in 1988. In 1986-1988 Plasmodium falciparum was responsible for 74% cases of the total number, followed by P. vivax (21%), P. malariae (2.2%) and P. ovale (1%). 86% of the imported cases was acquired in African countries, 8% in Asia and 3% in South America. As far as travellers categories are concerned, workers represented 46% of the total population, tourists 37%, seamen and aircrew 2% and strangers coming from endemic malaria areas and travelling to Italy 16%. In 1986, 1987 and 1988 three, four and two deaths respectively, due to malaria, were reported.

Plasmodium berghei: gametocyte production, DNA content, and chromosome-size polymorphisms during asexual multiplication in vivo.

In this study the DNA content and the karyotype of clones of Plasmodium berghei, which differed in the capability to produce gametocytes, were determined. The DNA content per haploid genome was established by cytofluorometric methods after staining of the haploid merozoites with DNA-specific fluorescent dyes. Field inversion gel electrophoresis was used to establish the number and size of the chromosomes. Parasites of a high gametocyte producer clone (original HP) and a low producer clone (original LP) contained 13 to 14 chromosomes in the size range of 0.5-3.8 megabase. In four independent experiments parasites of the original HP clone were maintained in mice and were mechanically transmitted for prolonged periods of time (up to 90 weeks). During the transmission period the capability to produce gametocytes decreased in all four lines. After mosquito transmission of parasites from these low producer lines, the gametocyte production returned to the level of the original HP clone. The total DNA content per haploid genome of low producer parasites was not significantly different from that of HP parasites. During prolonged periods of asexual multiplication of the HP clone in vivo, changes in the relative size of several chromosomes were detected. Mosquito transmission of the original HP clone did not result in a change of the karyotype. However, novel karyotypes were readily observed after mosquito transmission of parasites of the low producer lines. The decrease of the capability to produce gametocytes did not necessarily involve detectable changes in DNA content or in karyotype.

[Imported malaria in Italy: retrospective analysis from 1960 and update for 1986-1988]. / Malaria di importazione in Italia: analisi retrospettiva dal 1960 e aggiornamento 1986-1988.

The trend of imported malaria cases in Italy from 1960 to 1988 is discussed. Comparative analysis of its incidence in the last three years is also presented. Since 1985, a rapid increase has been recorded with 191 cases in 1986, 287 in 1987 and 350 in 1988. In 1986-88 Plasmodium falciparum has been responsible for 74% of the total number, followed by P. vivax (21%), P. malariae (2%) and P. ovale (1%). 86% of the imported cases have been acquired in African countries, 8% in Asia and 3% in South America. As far as travelers categories are concerned workers represent 45.6% of the total population, tourists 36.6%, seamen and aircrew 2.1% and strangers coming from endemic malaria areas and traveling to Italy 15.7%. In 1986, 1987, and 1988 one, two and two deaths, respectively, due to malaria, are reported.

Re-examination of earlier work on repetitive DNA and mosquito infectivity in rodent malaria.

Previous results, relating mosquito infectivity to percentage of repetitive DNA in the genome of Plasmodia, are re-examined in the light of the finding that a parasite line used in the previous studies and classified as Plasmodium berghei NK65, was a mixed infection, where the major component appeared to be Plasmodium yoelii. This conclusion was reached through cloning and isoenzyme typing of different clones. Isoenzyme typing alone is not sufficiently sensitive to reveal contamination amounting to less than 20% in a mixture. Attention is drawn to the risk inherent in work with uncloned lines, where the proportions of species or sub-species present may vary according to line history and gametocyte viability.

Inheritance of post-vaccinal resistance against Plasmodium berghei infection in mice.

The protective effect of specific vaccination against Plasmodium berghei (P. berghei) was compared in terms of survival percentage in DBA/2, C3H, outbred albino mice and in two lines of mice produced by selective breeding for either high or low antibody responsiveness to sheep erythrocyte (H and L lines respectively). The efficacy of induced protection varies according to genetic constitution. It is very strong in H line and albino mice, intermediate in DBA/2 and very weak in L line and C3H. The inheritance of post-vaccinal resistance to infection was studied in F1 hybrids and backcrosses between C3H and the other lines. The control was polygenic in all cases. The dominance of the characteristic depends on the strain combination. On the whole the results suggest the non-identity of the genes controlling protection in the various lines. The lack of a quantitative parameter for a more precise genetic analysis of protective immunity in inbred lines is stressed, since both anti-P. berghei antibody production and parasitaemia proved to be unreliable.

[Plasmodium berghei: antibody response and protective immunity induced by vaccination]. / Plasmodium berghei: risposta anticorpale e immunità protettiva indotta da vaccinazioni.

The authors have studied the behaviour of Swiss mice and of 5 inbred strains of mice in order to investigate: the protective effect, in the homologous infection test, of six vaccine inoculations of irradiated parasites belonging to two strains of Plasmodium berghei: ISTISAN and K173; the capacity to produce humoral antibodies after vaccine treatments and during infection; the probable correlation between the high antibody titre and the protection against infection. The results of the present study show that the antibody response plays a precise role in the immunity induced by vaccination. There is a certain degree of correlation, which is more evident for K173 vaccine, between the level of antibody response during infection and the protective efficacy of vaccination.

[Epizoology of leishmaniasis in the province of Foggia: leishmaniasis in the dog]. / Epizoologia della leishmaniosi in provincia di Foggia: la leishmaniosi del cane

The authors value the sensibility and the advantage of the different serological tests for the diagnosis of canine leishmaniasis (immunodiffusion, complement fixation and immunofluorescent tests) and give the results obtained from an epizoological survey carried out on dogs in the province of Foggia (Italy). The immunofluorescent test, whose positivity sera titre has fixed at the diluition of 1:10, resulted the most appropriate. In more than 400 animals examined, all from the 50 communes of the province of Foggia, the infection level of the dog by leishmania resulted to be 7.42%. If the three geographical zones, in which the province has been subdivided, are considered, this level varies from 10.21% for the subjects from the Gargano promontory, to 6.89% for those of the Subapennine Dauno, and to 5.55% for those of the Apulia plateau.