disease 251
However, pathogens that require arthropod vectors and/or alternate hosts tend
not to occur everywhere equally because of the ecological requirements of the vectors
and alternate hosts. As a result vector-borne diseases with particular temperature
requirements, either for the vector or the pathogen or the alternate host if any, may
well be restricted to particular geographical areas. In the case of the Mediterranean,
the northern limits of the region as defined in climatic terms do happen to coincide
very approximately with the northern limits of the distribution in the past of two
major diseases caused by parasitic protozoa, first Plasmodium falciparum, the most
dangerous of the five species of human malaria now known, which requires a certain
temperature to complete its development (sporogony) inside the mosquito vector
(Sallares, 2002: 102), and second, leishmaniasis. Malaria is very well documented in
historical texts as far back as records go in the Mediterranean and Near Eastern world,
both in classical Greek and Roman literature (Sallares, 2002) and also in ancient
Mesopotamian literature (Scurlock and Burton, 2005: 36–37; Stol, 2007). Galen
records that he suffered from tertian fevers in four out of the five years that he spent
in Alexandria (Grmek and Gourevitch, 1986).
Leishmaniasis in contrast is less well documented in the historical record, gener-
ally only being recognizable in early modern texts such as Alexander Russell’s descrip-
tion of the diseases of Aleppo in Syria in the eighteenth century (Russell, 1756) or
Mitford’s description of “Aleppo boil” in 1839 (Gooneratne, 1970), although its
presence in ancient Mesopotamian cuneiform texts has also been suggested recently
(Scurlock and Burton, 2005: 509–512). However, the evidence for leishmaniasis in
history is being dramatically increased by the research in ancient biomolecules, which
is transforming the entire field of disease history and enabling medical historians to
escape from the problems and uncertainties of retrospective diagnosis (Mitchell,
2011b). There is now evidence for leishmaniasis all the way from the bones of
Eleonora of Toledo (Nerlich et al., 2012), the wife of Cosimo I de‘ Medici in the
sixteenth century ce, back to the time of the Middle Kingdom in Egypt in the second
millennium bce (Zink et al., 2006). Its effect on the Medici family is not surprising
because there are still several foci of leishmaniasis in Tuscany today. Leishmaniasis has
reservoirs in other animals, unlike human malaria in Europe in the past, and so it
cannot be eradicated in the same way that malaria was eradicated from Europe. Thus
we may be sure that leishmaniasis, as well as malaria, was a component of the eco-
logical community of diseases in the ancient Mediterranean world, despite the lack of
evidence for it in ancient Greek and Roman documentary sources. The famous
Medici family of Renaissance Florence suffered from both leishmaniasis and malaria
(Fornaciari et al., 2010).
Consequently we have two diseases whose distribution was approximately cotermi-
nous with the northern limits of the Mediterranean climatic zone. The temperature
effects operate both on the parasites, such as those of falciparum malaria, and also on
their vectors. The northern limits of the distribution in the recent past of the mos-
quito species Anopheles labranchiae and Anopheles sacharovi, the most important vec-
tors of malaria in western and eastern Mediterranean countries respectively in the
past, approximated to the northern limit of the Mediterranean climate. This also
applies to the sandflies which transmit leishmaniasis. Both falciparum malaria and
leishmaniasis certainly exist in Africa far beyond the southern limit of the Mediterranean
climatic zone, even though the Sahara desert is indisputably a quite different