Do natural catastrophic events and exceptional climatic conditions also affect parasites?

Abstract

Parasites and parasitologists have always lived together in good and bad luck in a sort of forced marriage. In recent times bad luck certainly prevailed, because of increasing man-made emergencies such as wars, chemical disasters, but also because of natural disasters, amplified by climate change, that condition more and more parasite–host equilibrium. The symposium at the National Congress of the Italian Society for Parasitology, was a first occasion for Italian parasitologists to reason about ‘disaster parasitology’ and researchers’ responsibilities. Extreme weather events and their impacts on parasites’ epidemiology are illustrated, comparing disasters that recently occurred in Italy with literature data. In particular, the Sardinian Island was hit subsequently by fires and floods exacerbating the effects on ecosystems and parasite–host-relationships. Examples of Cryptosporidium outbreaks in man and Fasciola hepatica infections in various hosts after heavy rains are reviewed and effects of droughts on pasture borne parasites, such as gastro-intestinal nematodes of ruminants are discussed. Heavy rains may also cause dissemination of toxic substances released accidentally from chemical plants as happened e.g. in Milan province (IT) after the dioxin hazard. The overlapping effects of strictly man-made disasters with climate change dependent extreme weather events is further challenging the understanding of what are the consequences of disasters on ecosystems and parasite epidemiology.GIS applications combined with AI programs may help to face the complex challenges, allowing the collection and analysis of spatial/temporal data at whatever level desired. Examples illustrated in the article suggest their employment also in a more systematic, prevention-oriented manner.

Keywords: Drought; fire; flood; natural disasters; parasites.

Graphical abstract

Figure 1.

Sheep washed by the flood on a tree, north-eastern part of Sardinia Island (Italy), November 2013.

Figure 2.

Sheep washed by the flood up to the sea, north-eastern part of Sardinia Island (Italy), November 2013.

Figure 3.

Carbonized sheep in the area of Montiferru (central-western area of Sardinia), after the fire in summer 2021.

Figure 4.

The timeline of Italian disaster examples, affecting the parasite environmental habitats, their survival and capacity to propagate.