Lions and diseases
Gulamabbas Mohammedali
Sunday News; Sunday,September 10, 2006 @00:05
LIONS in Serengeti national park were in grave danger from diseases that originated in dogs leaving in surrounding villages. One-third of the entire population of lions in the park had died from canine distemper from 1994 through 1997. Other predators such as silver - backed jackals, bat eared foxes and the very rear African wild dogs were also dying from the disease.
More than one thousand lions in the Serengeti had died from canine distemper since 1993. Dogs pass the disease to hyenas who then act as the primary carriers of the disease because they travel long distances and mix with other predators that kills.
To stop this spread, a programme was set up to vaccinate the dogs in surrounding villages to stop this disease at its source and protect all species stricken with it. The first round of vaccinations were to target 10,000 dogs in 10 km circle west of the park. The dogs were vaccinated for parvo virus, rabie and cannine distemper. The effects of cannine distemper are brutal. The fatal neaurological disease is characterised by grandmal seizures. Strien animals can suffer for days, weeks or even months before they finally succumb or are eaten by other predators.
This is not the first time a disease has spread from domesticated animals to wildlife in the Serengeti region. In the 1940s, a disease called rinderpest spread to wildlife from cattle and killed thousands of wild beests and gazelle. Rinderpest was brought safely under control through cattle vaccinations, but the threat from cannine distemper and rabies were still very real.
"Another outbreak of disease could devastate wildlife populations." It could also endanger human health. If rabbies were to spread to wildlife in the Serengeti, the results could be catastrophic.
A number of lions in the Ngorongoro crater have been knocked severely by several bouts of acute disease over the past 40 years. Between 1994 and 2001, outbreaks of cannine distemper virus had kept the lion population low, with numbers dropping to just 29 individuals in 1998.
The scientists suggested that climatic change, or an increasing local human population could be to blame
The Ngorongoro crater in Tanzania is truly a unique place. The crater, 610m deep and 260 km squared, is a microcosm of East Africa scenery and wildlife.
Many crater animals, like lions, live there and there alone, making it a near - contained mini biosphere. The lions of Ngorongoro crater have been monitored closely since the 1960s.
In large carnivores, like lions, one might expect food supply to be the main limiting factor. But in recent years, diseases are the more likely restriction. There are probably enough prey animals like Buffalo in the Ngorongoro crater to support about 120 lions.
But at various times over the last 40 years lion numbers have dropped well below that and in the last 20 years there have rarely been more than 60 in the crater. It is believed that disease is the biggest culprit in this population dip.
In 1962, the crater lion population crushed from about 100 to 12, which coincided with an outbreak of blood sucking stable flies. After this severe knock, the population climbed again, to reach over 100 by 1975. Lion numbers then simmered away at fairly stable proportions until 1983, when they went into decline again reaching a low point of 29 individuals in 1998. "Diseases appear to be the only factor that has held the crater lion population below its carrying capacity for the past 20 years."
Although any diseases threaten lions, cannine distemper virus (CDV), which normally affects dogs, has been a particular menace to the big cats. The cause of the increase in level of disease is not known. It is assumed that there were many humans in area then, and with then came domestic dogs - which carried CDV. Diseases outbreaks could be exacerbated by climate change. In the last 20 years East Africa has suffered many more droughts and floods, which seem to coincide with bouts of disease.
"The weather in East Africa was more variable in the 1990s than in the 1970s and 1980s and four lions death coincided with droughts and flood."
The 1962 (stable fly) plague coincided with heavy floods that immediately followed severe droughts in 1961, and the 2001 CDV epidemic followed the drought of 2000. Whatever the causes of the diseases outbreak, they put the fragile population of Ngorongoro crater lions at serious risk.
Endangered populations could remain at serious risk even with a large, stable food supply and no real threats from competing species.
Unless rural Africans benefit far more from ecotourism the "shocking" decline of the continents remaining lions will continue. Fewer than 20,000 lions may now survive in the whole of Africa, though they do not face immediate extinction.
