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

summers as the marshes dried out.⁶⁸ The pseudo-Aristotelian Problems noted that after a wet spring and dry summer the autumn is lethal to all age-groups, but especially to children, the main victims of P. falciparum malaria when it is endemic.⁶⁹

That even large lakes were subject to major fluctuations in central Italy in antiquity is shown by the example of the former Lago di Fucino, in the territory of the Marsi beyond the Monti Simbruini, which experienced great fluctuations in its water level according to Strabo. Julius Obsequens recorded that the Lago di Fucino overflowed its banks for five Roman miles in all directions in 137 .

Draining it was another of Julius Caesar’s unfulfilled dreams. The emperor Claudius attempted at great expense to drain it. However, Tacitus’ account, stating that the tunnel that was originally constructed did not even reach half-way down the lake, illuminates the difficulties faced by the Romans in effectively performing major drainage operations. Claudius’ works were neglected by Nero.

Later attempts in antiquity were made by Trajan and Hadrian, but the lake was not drained completely and permanently until the operations of Prince Torlonia commenced in  1862.⁷⁰ The plain ⁶⁸ Anon. (1793: 23); Dobson (1980: 378–80); see Ch. 5. 4 below.

⁶⁹ [Aristotle,] Problems 1.19.861b: Di¤ t≤, ƒ¤n toı ceim0noß bore≤ou ka≥ toı πaroß not≤ou ka≥ ƒpÎmbrou tÏ qvroß l≤an aÛcmhrÏn gvnhtai, qanat0deß g≤netai tÏ metÎpwron p$sin, m3lista d† to∏ß paid≤oiß, ka≥ to∏ß £lloiß d† dusenter≤ai ka≥ tetarta∏oi crÎnioi g≤nontai ƒn aÛt‘ (Why is it that if the north wind prevails in winter, and the spring is damp and rainy, and the summer is very dry, then the autumn is deadly to all, particularly children, while others suffer from dysentery and prolonged quartan fevers?). This is a typical description of a year ending with an autumn epidemic of malaria. The pseudo-Aristotelian Problems also contains a lot of other material on the seasonality of disease patterns.

⁷⁰ Strabo 5.3.13.240C. Leveau (1993) discussed the ideology of Roman attempts to manage the Fucine Lake. Pratesi and Tassi (1977: 222–5) described the modern environment of the basin. Giraudi (1989) suggested that the lake’s water level was low during the period c.300

– 200, followed by the Roman drainage, which he unjustifiably assumed to have been a complete success. The words of Julius Obsequens for 136 , M Lacus Fucinus per milia passuum quinque quoquo versum inundavit—(the Fucine lake overflowed its banks by five miles), show that Giraudi’s generalizations must be taken cautiously. For the problems which beset the Roman drainage schemes see Tacitus, Annals 12.56–7; Pliny, NH 36.24.124; Suetonius, Claudius 20–21; Dio Cassius 61.33.5. Thornton and Thornton (1985) discussed the drainage works. The inscription CIL 9.3915 and SHA Hadrian 22.12 record the efforts of Trajan and Hadrian.

72

Ecology of malaria

of the former Lago di Fucino might be too cold today for P. falciparum, situated as it is at an altitude of 669 metres (but not for P. vivax). However, the water of the lake exercised a moderating influence on temperature in the past. In antiquity the lake was once surrounded by a primeval forest, Angitia, mentioned by Virgil.⁷¹

Deforestation of the mountain slopes encircling the basin, coupled with the effects of the modern drainage operation in 1862, significantly altered the microclimate of the region. It is now colder than it used to be, with more severe winter frosts. These climatic changes have eliminated the olive trees which formerly grew around the lake. They also gradually helped to convert the Fucine basin into an area of anophelism without malaria by the end of the nineteenth century. However, in the immediate aftermath of the drainage operations which commenced in 1862 it was observed that the frequency of malaria actually increased, presumably because the drainage left exposed areas of damp soil which had previously been permanently flooded, creating new breeding sites for mosquitoes. The example of the Fucine Lake illustrates the complexity of the environmental variables that have to be taken into account to understand the distribution and frequency of malaria. The modern experience suggests that the partial drainage achieved temporarily by Claudius would have actually increased the frequency of malaria around the remainder of the lake, especially considering that the climate as a whole was in any case warmer for much of the period of the Roman Empire (see Ch. 4. 5

below). The theme of unintended side-effects of human activity will recur in the course of this chapter.⁷²

Mosquito larvae can grow very rapidly, in a few days. They may live in moist ground for three or four days. Once they have pupated, it does not matter if the water of the pool evaporates completely and the ground completely desiccates, since it suits the adult mosquitoes to emerge from completely dry soil or sand, for example sand from the banks of the river Tiber as shown by Celli’s and Grassi’s experiments.⁷³ Gradual desiccation of pools during ⁷¹ Virgil, Aeneid 7.759–60.

⁷² North (1896: 117–18) noted the temporary increase in malaria during the modern drainage operations, although by the end of the nineteenth century the Fucine basin had become one of the areas of anophelism without malaria discussed by Hackett and Missiroli (1931). Hare (1884: ii. 190) and Letta (1972: 13 n. 12) also commented on the presence of malaria around the lake in the early modern period.

⁷³ Celli (1900: 78); Sambon (1901 a: 199).

Ecology of malaria

73

12. The coastal forest of the Parco Naturale della Maremma, in the direction of the Ombrone river valley, and the Canale Scoglietto Collelungo.

In the past the water in such drainage canals often flowed too slowly to prevent mosquitoes breeding in them. The pine forest (principally Pinus pinea) on the left was planted in the nineteenth century. The Monti dell’

Uccellina (to the right and behind the line of sight) are covered by oak forests.

the summer was assisted by hot, dry south winds, which were associated with malaria by Theophrastus and other