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

⁶¹ Palladius 1.7.4: palus tamen omni modo vitanda est, praecipue quae ab Austro est vel occidente et siccari consuevit aestate, propter pestilentiam vel animalia inimica quae generat.

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poses. Their larvae generally require water that is clear, in contrast to the larvae of Culex mosquitoes (non-transmitters of human malaria) which are happy in dirty water, although Anopheles larvae were also found in puddles of dirty water at Grosseto in the nineteenth century.⁶² In addition, the water must be well oxygenated.

This explains the success of spreading oil on the surface of pools as a modern control measure. Anopheles larvae prefer pool and canal margins where there is plenty of vegetation, which provides cover from predators. Sambon noted that at Ostia in the summer of 1900

all the pools and canals had enormous numbers of frogs, several species of fish (especially the young of the grey mullet), and swarms of dragonfly larvae and water beetles.⁶³ Consequently large permanent lakes are not necessarily any better for mosquitoes for breeding purposes than very small pools, which are only filled with water seasonally. Strabo noted that the large inland lakes of Tuscany, such as Vico, Bolsena, Chiusi, and Bracciano, produced substantial quantities of fish for the city of Rome.⁶⁴ A series of lakes along the coasts of Tuscany and Latium, such as the Prilius lacus near Grosseto and the lakes near Circeii, were also extensively exploited for fishing in Roman times.⁶⁵ In addition, the Romans created numerous artificial fishponds ( piscinae) attached to coastal villas.

Such fishponds have been found at many locations along the coast of Etruria, such as Cosa, Torre Valdaliga, Grottacce, Pyrgi, and also in Latium and Campania. Recent research into these artificial fishponds concludes that their water was usually brackish: The archaeological evidence is decisive in showing that the Romans preferred brackish conditions for their seaside piscinae . . . Arrangements for mixing salt water and fresh water to create a brackish environment were ⁶² Celli (1900: 79) mentions Grassi’s observations at Grosseto. Austen (1901) discussed the differences between Anopheles and Culex mosquitoes.

⁶³ Sambon (1901 a: 199).

⁶⁴ Strabo, 5.2.9.226C. Quilici (1979: 104–6), noting the frequent presence of fish in offerings in archaic tombs in the Roman Forum, stressed that the River Tiber itself was an important source of fish in the early stages of Roman history, although it was wholly inadequate (and heavily polluted) by the time of the Roman Empire, cf. Nutton (2000 b: 66) and LeGall (1953: 267–8, 318–19). Pratesi and Tassi (1977: 43) described the rich fauna of fish in the modern Lago di Bolsena. Dennis (1878: 30) interpreted the prodigy in Livy 27.23.3, Volsiniis sanguine lacum manasse (the lake at Volsinii flowed with blood), as a sign that the area around the Lago di Bolsena was becoming unhealthy in the late third century . Magri (1999: 173) noted that the settlement of Monte Bisenzo nearby was finally abandoned in 1816 because of mal’aria arising from the Lagaccione marsh.

⁶⁵ On the Prilius lacus see Cicero, pro Milone 74, with Celuzza (1993: 92–3) for the identification of the site of Clodius’ villa; Pliny, NH 3.5.51.

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common features in Roman fishponds and are well represented in the archaeological record from both the late Republic and early Empire.⁶⁶

The chemical composition of water is very important for the breeding of Anopheles mosquitoes. Since they certainly can breed in brackish water, so long as it is not too salty, the water of some of these fishponds could have been favourable for malaria. The fish were an unfavourable factor for mosquito larvae, but a great deal would have depended on how much vegetation was present in these artificial fishponds. In any event, it is certain, as will be seen, that the coasts of Etruria and Latium were severely affected by malaria in the Late Republic and Early Empire. Strabo (quoted in Ch. 6 below) described the area around Circeii, which was a centre of fish farming, as pestilential. Consequently neither the hydraulic works of the fishponds nor their fish seriously impeded mosquito larvae.

The vicinity of the large inland lakes mentioned by Strabo was certainly heavily infested with malaria in the early modern period.

Nevertheless, Anopheles larvae can flourish at least as well in the small depressions in the ground, only containing water for a few months each year, that frequently occur on the lower slopes of hills in Latium and Tuscany, and particularly in the undulating terrain of the Roman Campagna. All the literature on the early modern Roman Campagna lays stress on the importance of small seasonal pools and puddles for the generation of malaria. Tommasi-Crudeli, scaling up the results of a small field survey to provide an estimate for the whole Roman Campagna, suggested that there were quite literally thousands of breeding sites for mosquitoes in the Roman Campagna in the nineteenth century, before many of the modern drainage operations. This was also the origin (besides rivers and streams) of much of the malaria in the past in southern Italy, where it frequently occurred in the absence of marshes or large lakes.⁶⁷ Consequently the most dangerous wetlands were those which tended to dry up in the summer, as Palladius observed, since there were no predators to eat the mosquito larvae. The ⁶⁶ Higginbotham (1997: 16); Rustico (1999) has also discussed the Roman fishponds recently.

⁶⁷ e.g. North (1896: 113–15) emphasized that pools which dried up in summer were very dangerous; Tommasi-Crudeli (1892: 34). Tommasi-Crudeli and North also discussed this phenomenon in the region around Mantua, showing that it was not confined to Lazio, cf.

Dobson (1997) on England.

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anonymous author of a late-eighteenth-century discourse on mal’aria noted that many of the localities in the Roman Campagna which were marshy in winter became completely dry in summer.

Similarly in the marshlands of early modern England mortality from P. vivax malaria increased after dry