Malaria and Rome: A History of Malaria in Ancient Italy, Robert Sallares [reading a book TXT] 📗

Ecology of malaria

93

not profitable to maintain a military camp continuously in unhealthy areas.¹²⁶

Not surprisingly, the enemies of Gaius Gracchus were delighted when he was sent as quaestor to Sardinia. They doubtless hoped that he would not return. The Roman army with which Gaius Gracchus was serving did indeed suffer severely in the winter. This was probably the result of the synergistic interactions (discussed in detail in Ch. 5. 2 below) of P. falciparum malaria with the respiratory diseases of winter.¹²⁷ But Gracchus himself did return. A passage in Tacitus also shows that the Roman Senate was well aware that people sent to Sardinia were likely to succumb to the bad air of the island:

The Senate decreed that four thousand freedmen of suitable age, who had been corrupted by this superstition, should be sent to the island of Sardinia to curb bandits there, and if they died owing to bad air, the loss would be of no consequence.¹²⁸

For the poet Martial Sardinia was a synonym for death.¹²⁹

4.4 M , ,  

After this digression on Sardinia, we must return to the environmental factors which influence the distribution of mosquitoes.

Besides the distribution and chemical composition of bodies of water, man-made structures undoubtedly also made a significant contribution to the spread of malaria in Italy in antiquity. In the nineteenth century  it was noticed that malaria tended to spread along the new railway lines that were being constructed in Italy.

¹²⁶ Strabo 5.2.7.225C: noser¤ g¤r Ó n[soß toı qvrouß, ka≥ m3lista ƒn to∏ß eÛkarpoısi cwr≤oiß . . . oÈ d† pempÎmenoi strathgo≥ t¤ m†n åntvcousi, prÏß 4 d’ åpaud0sin, ƒpeid¤n m¶

lusitel[ trvfein sunec0ß ƒn to∏ß nosero∏ß stratÎpedon.

¹²⁷ Plutarch, Tiberius and Gaius Gracchus 22.4 and 23.2, ed. Ziegler (1971): jscuroı d† ka≥

nos*douß ‹ma ceim0noß ƒn SardÎni genomvnou (there was a severe and unhealthy winter on Sardinia). Cicero, epist. ad Quintum 2.3.7 was aware that on Sardinia (in contrast to Latium) there was some risk of transmission of malaria even in winter. Livy 41.6.6 describes the crip-pling of another Roman army on Sardinia by pestilence in 178 . Logan (1953: 176–92) discussed the epidemiology of malaria in Sardinia. Strabo’s evidence that Roman commanders were concerned about the mortality from malaria on Sardinia shows that the theme of Curtin (1989) was already being consciously considered (if only in qualitative terms) two thousand years before the period upon which Curtin chose to focus.

¹²⁸ Tacitus, Annals 2.85.3: factumque patrum consultum ut quattuor milia libertini generis ea supersti-tione infecta quis idonea aetas in insulam Sardiniam veherentur, coercendis illic latrociniis et, si ob gravitatem caeli interissent, vile damnum.

¹²⁹ Martial 4.60.

94

Ecology of malaria

15. Reconstruction of a typical traditional peasant hut in the Pontine region, on display in the Parco Nazionale del Circeo. Spraying of the interior walls of dwellings with DDT broke the malaria transmission cycle in Italy by irritating the mosquitoes and driving them outside, where it was too cold for P. falciparum sporogony in the mosquito and frequently too cold for the mosquito itself, according to the explanation given by Mario Coluzzi. The mosquitoes became irritated after about five minutes and flew away before they had absorbed enough DDT to actually kill them (which would have taken about forty-five minutes). Since the irritant effect drove away the mosquitoes before they had absorbed enough DDT

to actually kill them, natural selection did not operate on mosquito populations in Italy and they did not develop resistance to DDT. However, the same strategy is less effective in Africa today because both the mosquitoes and the malaria parasites are happy outdoors in the tropical heat.

For example, being sent to work on the forty-four kilometre stretch of railway line between Taranto and Torremare was a death sentence, according to Bonelli. The Fiumicino–Ponte Galera and Rome–Chiarone routes in Lazio ranked among the most lethal railway lines in Italy. It was realized that the construction of embankments and cuttings for railway lines often interfered with natural drainage patterns and altered the level of the water table. In addition, the pits which were excavated to provide earth for Ecology of malaria

95

embankments often subsequently became filled with water and provided excellent breeding sites for mosquitoes.¹³⁰

In antiquity Strabo explicitly commented on Roman road building in Latium and noted the cuttings through hills and embankments across valleys which Roman engineers designed for their roads. Similarly Pliny noted the roads cut through mountains.¹³¹

Modern experience in Italy in the nineteenth century with railways suggests that Roman (and also earlier Etruscan) road building would have played a significant role in creating favourable new breeding habitats for Anopheles mosquitoes. Similarly ‘road building was linked intimately with the proliferation of malaria’ in Bengal in India during the British rule in the nineteenth century .¹³² The ancient accounts of his life state that Gaius Gracchus organized a considerable volume of road construction in Italy, after his return from Sardinia. Modern historians have failed to realize the irony of his work. By having roads built, Gracchus unwittingly assisted the spread of malaria in those very same depopulated parts of Italy which he desired to rejuvenate.¹³³

The nuraghi of Sardinia served to introduce the question of the design and construction of housing, another very important topic.

As Varro put it:

The situation of villas, the size of the buildings, and the directions in which colonnades, doors, and windows face, are matters of very great interest.¹³⁴

Unfortunately, as has often been observed by modern scholars, the atrium of Roman houses contained a pool of rainwater in the impluvium, a possible habitat for mosquito larvae (so long as there were no fish in it). It is not clear if the presence of the impluvium was important in practice in relation to malaria. Eugenia Tognotti, in her book on malaria in Sardinia, noted that A. labranchiae likes houses which are dark inside, providing cover, with small windows, ¹³⁰ Bonelli (1966: 667 n. 11), quoting the Inchiesta Iacini; Tognotti (1992: 25); Celli (1900: 147).

¹³¹ Strabo 5.3.8.235C: πstrwsan d†