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.

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.

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.

Summary 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 F| 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.

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.

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.

Viene descritta una nuova via efferente della catena ganglionare diPeriplaneta americana, che origina nel 1° ganglio addominale, raggiunge i nervi cercali (NXI) ed è interrotta da sinapsi in ciascuno dei sei gangli addominali. Vengono riferiti la velocità di conduzione nei connettivi ed i tempi di trasmissione a livello dei gangli.

The effect of black widow spider venom [crude gland extract (CGE), gland lumen venom (GLV), or from direct bite] on the cardiac activity of Periplaneta americana was assayed both in vivo and in vitro. It was shown that these different forms of venom in all cases blocked the cockroach heart-beat. Both CGE and GLV showed a selective activity on the heart function compared with their effect on the CNS. It is suggested that cardiac block is due to impairment of either the cardiac nerve ganglia function or the myocardial neuromuscular junctions, or of both of them. The mode of action of the toxic effects on the heart is discussed. Experiments with antiserum from CGE indicate that the antigenic fractions of CGE and GLV affecting the heart function, as well as those affecting the insect motor functions, are common to both toxic materials.

By combining gel filtration on Sephadex G-15 and G-10 and ion exchange chromatography on Cellex CM, 6 different peaks of physiological activity were separated from aqueous extracts of Periplaneta americana corpora cardiaca. The following physiological activities were assayed on the fractions; heart accelerating (HA), hyperglycaemic (HG), and increasing the frequency of the spontaneous firing recorded from nerves leaving the 6th abdominal ganglion (SFI). The 6 peaks had the following activities; (1) HA and SFI (2) HA, SFI and HG (3) HG and SFI (4) SFI (5) HA and (6) HA. Each was inactivated by treatment with trypsin. Analogies with physiologically active factors separated by other authors from similar tissue extracts are discussed, e.g. the possible identity of the active material present in peak 1 with neurohormone D of Unger and with factor P1 of Brown. None of the peaks of activity corresponds to the elution characteristics of a pure sample of 5-hydroxy-tryptamine.