Asia. During the late 1950s and early 1960s when the Soviet Union used poison to effectively bring down wolf numbers, the number, as well as the range of moose, wild boar and red deer increased. Caspian seals were valued as fur bearers in the Soviet industry, and in a three-week period in February 1978, wolves were responsible for the wanton killing of numerous seals on the Caspian sea near Astrakhan. Between 17 and 40% of the seals in the area were estimated to have been killed, but not eaten. Wolves and the spread of disease Some hunt proponents argue that large numbers of wolves are central to the spread of numerous infectious diseases because of their nomadic nature. Diseases recorded to be carried by wolves include rabies, brucella, deerfly fever, listeriosis, foot and mouth disease and anthrax. Wolves are major hosts for rabies in Russia, Iran, Afghanistan, Iraq and India. Wolves in Russia have been recorded to carry over 50 kinds of harmful parasites. A 10-year study in the former Soviet Union showed that in some regions, every successful wolf litter in spring coincided with a 100% increase in cestode infections in moose and wild boar, with some specimens having up to 30-40 cysts. It also showed that where wolves were absent, the number of cysticercosis-infected wild ungulates was much less. Although they by habit carry harmful diseases, large wolf populations are not negatively influenced by epizootic outbreaks as with other canids, and thus some hunting proponents argue that disease cannot be a guarantee of naturally controlling wolf numbers. Attacks on humans The absence of a global review, and the language barrier having partially hindered the flow of international information has led some international groups to level criticism at some wolf advocates, claiming that they have extrapolated America's general lack of negative experiences with wolves to the rest of the world, whilst ignoring the differing histories and cultures which lead to diverse interactions with the animals. Hunting proponents argue that wolves with no negative experiences of humans are more likely to encroach upon human settlements and attack people, citing for example the differences in attitudes toward the public distribution of firearms in America and Eurasia as examples as to why nations on both continents have differing accounts of wolf aggression. Hunting wolves is reasoned to maintain shyness in wolves, an idea which is correlated by a modern account demonstrating that