Thalassaemia and malaria

Thalassaemia and malaria

Antonio Tagarelli, Anna Piro, Giuseppe Tagarelli

From the data collected by the World Health Organization we learn that thalassaemia is present, with a relatively high frequence, in the long Sub-tropical belt and in a part of the temperate zone extending through Europe, Asia and Africa. In these areas still live about 180 million of healthy carriers, of whom 10 million live in Europe and in the Mediterranean countries and a good 2 million in Italy.
Though thalassaemic healthy carriers are present with a variable frequence in all Northern Europe countries, they are much more in the Mediterranean ones, especially in Greece, Cyprus island, Kurdistan, Turkey, Syria, Lebanon, Israel and in Northern Africa countries. Relatively high frequencies are found in all southeastern Asia countries.

Distribuzione nel Vecchio Mondo della Talassemia e della malaria

The Old World’s distribution of Thalassaemia and Malaria.

Correlazione della talassemia (A) con la malaria

Correlazione della talassemia con la malaria

Correlation of thalassaemia(A) and malaria (B) and Greek sites (C) (from: Talassemia: Silvestroni E., Bianco I.; 1982; from: Malaria: Ministero dell’Interno. Direzione Generale della Sanità pubblica, 1923; from: Siti magno-greci: Manfredi V.M., 1996).

In Italy thalassaemia is scarcely frequent in the center and north of the country, except in the area surrounding the river Po mouth, while it is more spread in the southern and insular areas. Its presence in the center and north is due to southern people’s migrations, while Southern Italy’s high frequence is connected to historic and environmental reasons. This area as well as Sicily was strongly colonized by Greek people from the 8th to the 6th century, in fact the latest researches of Molecular Genetics have proved the Greek origin of different genes equivalent to different kinds of thalassaemia found in Southern Italy. Moreover it is manifest how, in these same zones, thalassaemia’s distribution corresponds perfectly to malaria’s distribution. In 1949, Haldane had proved that there is a close relationship between thlassaemia and malaria in wide areas, and that this last acts as a positive selective factor towards the thalassaemic healthy carrier. In fact the malarial parasite is badly lodged in such subjects’ red cell, unsuitable to its survival. Therefore a healthy carrier has got more possibilities to procreate than a normal subject (more exposed to malarial infection) favouring in this way the rise of thalassaemia’s frequence.

Thalassaemia is an hereditary ematological disorder caused by the emoglobin’s (a red corpuscle’s protein carrying oxygen to the tissues) structural anomalies.
As with genetic mutations whose abnormal genes are connected to not- sexual chromosomes, this anomaly reveals with the greatest clinic vigour (heart complaints, endocrinologist, renal, hepatic and splenic problems and a strong anaemia) only if a person has inherited by both healthy carrier parents the altered gene (Cooley’s disease or thalassaemia major).

REFERENCES

Brancati C., Tagarelli A. (1982). Thalassemia Types in Calabria (Southern Italy). In: "Birth Defects: Original Article Series", vol. 18, n. 7
Haldane, J. B. S. (1949). Disease and Evolution. Ric. Sci. (Suppl.) 19, 3
Manfredi V.M. (Milano 1996). I Greci d'Occidente. Ed. A Mondadori
Silvestroni, E., Bianco, I. (1963). Le Emoglobine Umane. In: "De Genetica Medica", Ed. Ist. "Gregorio Mendel", Roma
Silvestroni, E., Bianco, I. (1982). Talassemie. In "Trattato di Medicina Interna", P. Introzzi, Ed. USES Scient. (III Edizione). Firenze
World Health Organization: Working Group on Community Control of Hereditary Anemias, (1987). A Short Guide to the Menagement of Thalassemia. Thalassemia Today. Proc. and. Medit. Meeting Thal., Ed G. Sirchia e A. Zanella, Milano