Malaria and Rome: A History of Malaria in Ancient Italy (10 page)

³⁵ Pliny,
NH
26.1–6.1–9; Plutarch,
Moralia
8.9.731b–734c.

40

Evolution of malaria

if malaria had been present right from the start. According to Dionysius of Halicarnassus a major attraction of Veii, the important Etruscan city captured by the Romans in 396  supposedly after a siege lasting ten years, as a place to live was the healthiness of its site, since there were no marshes or rivers nearby which generated ‘bad air’:

The city of Veii . . . had air around it that was extremely pure and very good for human health, since there was no marsh nearby to generate oppressive and evil-smelling vapours, nor any river from which cold breezes would arise at dawn.³⁶

Dionysius’ account implies that other localities were not so healthy.³⁷ Evidently it is not clear to what extent his account reflects the situation in his own time, rather than the fourth century .

The doyen of Etruscologists, Massimo Pallottino, relying on the work of Toscanelli, suggested that ‘life in the marshy areas of the Maremma and of the lower Po valley cannot be explained unless malarial infection was not yet common during the golden age of Etruscan civilization; but malaria must in fact have helped to hasten the decline of many Etruscan coastal towns in late Hellenistic times’.³⁸ Vetulonia (Etruscan
Vetlana
or
Vatulana
) is as good an example of the problem as any. It flourished in the eighth to sixth centuries , but then declined ‘rapidly and completely after the beginning of the Roman period’.³⁹ Vetulonia is located close to modern Grosseto, which has already been noted as one of the most intense foci of malaria in Italy in recent times.⁴⁰ Paestum (Poseido-

³⁶ Dionysius Hal. 8.15: Ó OÛientan0n pÎliß . . . πcousa . . . tÏn Ëperke≤menon åvra kaqar0taton ka≥ prÏß Ëgie≤an ånqr*poiß £riston, oÇte 1louß plhs≤on Ôntoß, Òqen 1lkontai bare∏ß åtmo≥ ka≥ dus*deiß, oÇte potamoı tinoß yucr¤ß 1wqen ånivntoß aÇraß.

³⁷ Since settlement at Veii declined from the second half of the third century  onwards (Patterson
et al
. (2000) ), the area may have become less salubrious later on. It was definitely unhealthy by the early modern period. Blewitt (1843: 520) described Veii as follows: ‘the modern village of Isola is in a state of complete decay . . . the appearance of the population, which seldom exceeds 100 souls, bears sufficient evidence of the prevalence of malaria during the hot months’.

³⁸ Pallottino (1975: 182); Toscanelli (1927); contrast Heurgon (1964: 100–6) on Etruria.

The survey of the archaeological evidence for Magna Graecia by Collin-Bouffier (1994) was rather inconclusive as far as malaria is concerned, cf. Livadie (1998).

³⁹ Pallottino (1975: 117).

⁴⁰ G. Radke in Pauly-Wissowa,
RE
VIII A.2 (1958), cols. 1874–80 s.v.
Vetulonia
. Michelucci (1981) noted some construction work at Vetulonia in the third century  and inscriptions dating to the second century , proving some continued occupation of the site, and there were still some rural settlements after the decline of the urban centre (Celuzza (1993: 83–8) ).

The neighbouring city of Roselle was also considerably smaller in Roman times than it had Evolution of malaria

41

nia) is an excellent example of the problem in so far as it affected the Greek cities in Italy. Paestum flourished in the sixth and fifth centuries , when its famous Doric temples were built. Subsequently, it suffered the debilitating effects of malaria, which became endemic in adjacent marshes, as Strabo describes.⁴¹ Nevertheless the site of the ancient city was not finally completely abandoned until about the ninth century , following Saracen attacks, when the settlement of Capaccio Vecchio, situated in a hilly location inland, began to flourish. This is a good example of a change in the settlement pattern in the medieval period whose ultimate cause had begun to operate at least a thousand years earlier in classical times.⁴²

In a way, the problem was even observed and discussed in antiquity. Livy raised the question of how the Volsci, coming from areas with a low population density (at least of free men) in his own time, could have raised military forces of the size attributed to them in the Roman annalistic tradition for their wars with the Romans in the fourth and fifth centuries .⁴³ It is interesting that Livy found the numerical strength of Volscian armies hard to believe, while simultaneously accepting the Roman census figures recorded by the annalists for the same period. Carmine Ampolo argued convincingly, following Beloch, that the Roman census figures for the period of the kings and the first half of the fifth century  indicate an unbelievably high population density for Latium Vetus, taking account of data for agricultural productivity, with its implications for carrying capacity, from as recently as the last century.⁴⁴ Evidently the disparity in Livy’s own time between the population of Rome and the population of the parts of Latium occupied by the Volsci was so enormous that Livy found it inconceivable that the two populations could once have been anywhere near equally matched, as the accounts of the Volscian wars available to him been during the Etruscan period (Celuzza (1993: 114) ). Eventually Roselle was abandoned in favour of Grosseto, which nevertheless suffered from malaria very early in its history in the medieval period. The Benedictine monks abandoned Grosseto because of malaria in 

1220 (Santi (1996: 132) ).

⁴¹ Strabo 5.4.13.251C: poie∏ d’ aÛt¶n ƒp≤noson potamÏß plhs≤on ejß 1lh ånaceÎmenoß (A neighbouring river flooding marshes makes the city unhealthy).

⁴² Pedley (1990: 17, 132, 163); Nutton (1971) discussed the fate of the neighbouring Greek city of Velia in relation to malaria.

⁴³ Livy 6.12.2–6, esp. 5:
aut innumerabilem multitudinem liberorum capitum in eis fuisse locis quae nunc vix seminario exiguo militum relicto servitia Romana ab solitudine vindicant
.

⁴⁴ Ampolo (1980: 24–30); Cornell (1995: 204–8).

42

Evolution of malaria

suggested. The two sides may once have been equal, but our conclusion must be that the sizes of the armies on both sides were exaggerated by later Roman historians. To understand the demise of the Volsci, it is essential to remember one other factor, besides Roman military prowess. The Volsci were new to the area, having invaded Latium from the Appennine mountain region in the early fifth century . Since
P. falciparum
malaria does not occur in the mountains (see Ch. 4. 2 below), the Volsci would not have had any sort of immunity to it. Consequently as malaria spread, its effects on the Volscian population in its new lowland territory are likely to have been particularly devastating.⁴⁵ Nevertheless the problem remains of reconciling the extreme antiquity (in terms of geological time) of
P. falciparum
malaria with its apparent late spread in Italy.

To try to solve the problem, it is necessary now to examine in more detail the ecology of malaria in Italy, both in recent times and in antiquity.

⁴⁵ Lancisi (1717: 123) expressed the opinion that the unhealthy air of the Pontine region led to the decline of the Volsci. In contrast to the Volsci from the hills, the Latins were etymo-logically ‘the people of the plain’ (Quilici (1979: 30) ).

4

The ecology of malaria in Italy

4. 1 M   

Before its eradication malaria was transmitted in Europe principally by mosquitoes belonging to a (complex of ) species that was originally called
Anopheles claviger
by Battista Grassi and later renamed
Anopheles maculipennis
. Roubaud and Wesenberg-Lund then noticed that malaria did not occur in many places where these mosquitoes were found, the puzzling phenomenon of
anophelism without malaria
. Anophelism without malaria was observed in Italy for example in such places as Colle Salvetti, Livorno, Massarosa, Naples, Pisa, Val di Chiana, and Viaréggio. In all these localities malaria appeared to have disappeared spontaneously by the end of the nineteenth century, even though there were still plenty of Anopheles mosquitoes around.¹ The resolution of the paradox of anophelism without malaria in Italy began when Falleroni, studying the mosquitoes of the Pontine Marshes, discovered that in places where malaria occurred the
A. maculipennis
mosquitoes always laid eggs which had one of two distinctive patterns, while in places where there was no malaria the mosquitoes produced eggs with other, different, patterns. It was then realized that what had been named
A. maculipennis
, a single species, was in fact a complex of different species with different habits. At that time the patterns on the eggs constituted the only morphological trait that could be used for differentiating these species.² Nine separate biological species are now recognized in the
A. maculipennis
complex in Europe (see Table 2). All the nine species may be identified in the fourth instar larval and adult female forms by chromosomal banding patterns, isoenzyme profiles, and DNA sequence analysis. Seven of the nine can be distinguished by specific patterns on the upper surface of their eggs and the form of the egg floats.
A. martinius
and A. sacharovi can be distinguished from the other seven species, but ¹ Hackett and Missiroli (1931); Hackett (1937); Fantini (1994); Gilles and Warrell (1993: 115–16).

² Falleroni (1926); Missiroli (1938: 9–10).

Ecology of malaria

44

Table 2. Palaearctic mosquito species in the
Anopheles maculipennis
complex Species

Author

A. atroparvus

Van Thiel (1927)

A. beklemishevi

Stegnii and Kabanova (1976)

A. labranchiae

Falleroni (1926)

A. maculipennis s.s.

Meigen (1818)

A. martinius

Shingarev (1926)

A. melanoon

Hackett (1934)

A. messeae

Falleroni (1926)

A. sacharovi

Favre (1903)

A. subalpinus

Hackett and Lewis (1935)

Source
: White (1978) and Ramsdale and Snow (2000). The
A. maculipennis
complex belongs to the subgenus
Anopheles
of the genus
Anopheles
, while tropical species that transmit malaria belong to the subgenus
Cellia
. Several other species in the A. maculipennis complex only occur in North America. Besides the mosquitoes of the
A. maculipennis
complex, the mosquitoes of the
Anopheles claviger
complex had a secondary role as malaria vectors in Europe (Zamburlini (1998); Schaffner
et al
.

(2000) ). Five other important mosquito species or complexes of species are mentioned in this book:
Anopheles gambiae
(the principal vector of malaria in tropical Africa),
Anopheles pharoensis
(vector of malaria in Egypt),
Anopheles plumbeus
(possible vector of malaria in England),
Aedes aegypti
(the vector of yellow fever), and
Aedes albopictus
(the original vector of dengue fever).

not from each other, by slight differences in adult morphology.

Three of these species were very important vectors of malaria in the past.
A. labranchiae
occurred in North Africa, Corsica, Sardinia, Sicily, central and southern Italy, parts of the Murcia and Alicante provinces of Spain, and Croatia.
A. sacharovi
occurred in mainland Italy, Sardinia, Greece, and the eastern Mediterranean, while
A.

atroparvus
was widespread in Spain and northern Europe, reaching its southern limit in Italy in Campania.
A. atroparvus
takes the place of
A. labranchiae
in northern Italy, while the two species coexist in central Italy. A fourth important vector-species,
A. superpictus
, occurs sporadically in southern Italy and Sicily. However, it does not belong to the
A. maculipennis
complex and its main geographical distribution lies in the Balkans and Near East. The study of chromosome translocations has shown that
A. labranchiae
,
A.

sacharovi
, and
A. atroparvus
are closely related to each other, within the
A. maculipennis
complex. All three can breed in brackish water in marshes near the coast, but also in fresh water in inland streams and (in modern times) in rice-fields.³

³ Ramsdale and Snow (2000) provide maps showing the current distribution of the Euro-

Ecology of malaria

45

3.
Anopheles labranchiae
, the most important mosquito vector of malaria in western Mediterranean countries in the past. According to Falleroni (1926: 565), who first identified it as a separate species, ‘it can be said that the winged insect does not live outdoors; it takes shelter and nourishes itself in houses, cowsheds, and pigsties’ (
l’insetto alato si può dire non viva all’aperto; si ricovera e si nutrisce nelle abitazioni, nelle stalle, nei porcili
). © The Natural History Museum, London.

The existence of regions in which there were lots of mosquitoes but no malaria, such as the northeastern coast of Italy around Ravenna (see Ch. 4. 2 below), is probably one reason why the ancient Greeks and Romans apparently failed to notice the connection between the periodic intermittent fevers of malaria and mosquito bites, as far as can be seen from extant literature. In Europe the theory that mosquito bites caused malaria was first proposed in print by Giovanni Maria Lancisi in his famous work
de pean species of
Anopheles
mosquitoes. In some cases these are different from their known historical distributions as a result of modern eradication campaigns.
A. sacharovi
is now thought to have been eradicated from Italy, and
A. labranchiae
from Spain. Coluzzi and Sabatini (1995) give information on current distributions in Italy. Proft
et al
. (1999) and Romi
et al
.