Source: Science, Vol.318. no.5855, pp.1372-1373 [abridged, edited]
When more than 2000 camels perished in Saudi Arabia this year [2007], the mysterious die-offs caused a nationwide furor. Investigations were launched, and camel “beauty contests” suspended. And when evidence mounted that the killer was not an infectious disease but rather a toxic substance in the animals’ feed, a government council demanded punishments and reforms.
But just as scientists in North Africa and the Middle East are expanding research into these seemingly impregnable desert juggernauts, the animals appear to be increasingly vulnerable to disease and toxins. Although epidemiological data are scarce — especially in the camel-rich but politically troubled nations of Somalia and Sudan — some scientists argue that the illnesses striking camels are changing. “We are seeing new diseases in camels, and we often don’t have a good explanation,” says Bernard Faye, chair of the newly formed International Society of Camelids Research and Development (ISOCARD).
In North Africa, there have been several unexplained dromedary die-offs during the past decade, but the incidents have not shown a consistent pattern so far. In the late 1990s, hundreds of camels perished in Ethiopia, followed by isolated incidents of dying animals showing similar symptoms — pneumonia and fevers, for example — in Kenya and Sudan over the past 7 years. Faye, who is working with Kenyan scientists to investigate the deaths there, says a small ruminant virus that normally infects cattle and sheep was the likely cause, but other pathogens were also found in the dead animals. “The biggest problem is getting blood and organ samples,” says Faye, a veterinary scientist with the French Agricultural Research Centre for International Development in Montpellier.
Another scourge of dromedaries, camelpox, is also a perennial suspect. The disease has been controlled with a vaccine in some regions, but Saudi scientists say it does not protect all camel populations. Other persistent or emerging camel diseases being scrutinized by North African investigators include tuberculosis, sleeping sickness [Trypanosomiasis], brucellosis, and rotavirus infections. There are no vaccines for such camel diseases, complains biochemist Mohamed Bengoumi of the Hassan II Institute of Agronomy and Veterinary Medicine in Rabat, Morocco.
In both North Africa and the Middle East, scientists have also noted an increase in the number of “food intoxications,” camel deaths or sickness caused by harmful substances in plants or in the livestock fodder the animals eat. Bengoumi says camels are highly susceptible to high-nitrogen plants as well as fungal mycotoxins, neither of which are typically found in dry regions.
Although mysterious camel deaths have occurred elsewhere in the Middle East and North Africa, no recent event matches the extent of this year’s [2007] Saudi die-off, during which at least 2000 dromedaries perished in a region mainly south of Riyadh, Saudi Arabia. One unofficial estimate placed the death toll at 5000.
Initial reports focused on the possibility of an infectious disease or intentional poisonings. But after an investigation by the nation’s agriculture ministry — which sent camel blood and fodder samples to both Saudi and outside labs — government officials asserted that the camels succumbed to contaminants found in their bran fodder: the antibiotic Salinomycin, a supplement in chicken feed that is toxic to camels, and a fungal species whose mycotoxins can damage some animals’ nervous systems.
The Saudi government has shared few details of its investigation with outside experts, which has puzzled camel scientists, who felt they could have contributed. “Many questions remain open,” says Faye. He suggests that the deaths may involve several factors, possibly including viral infections that suppress camels’ immune systems. But Saudi Arabia’s deputy agriculture minister for research, Abdullah Al-Obeid, says the lab tests showed no evidence of infectious disease. Steps are now being taken to improve the transport and storage of fodder for the nation’s half-million camels, he says.
Although Wernery’s lab hasn’t yet studied tissue samples from the recent deaths, he says “neither mycotoxins nor any known disease could have killed 5000 camels in that short span of time.” He favors the antibiotic explanation, noting that the Saudi die-off appeared similar in symptoms to the deaths of about 120 racing camels in Dubai a few years ago. The cause was also later determined to be Salinomycin in the fodder.
Whatever its origins, the Saudi debacle may help energize camel studies in the region. ISOCARD has been attracting new members, and Sudan has opened a camel research lab in Khartoum. In Saudi Arabia, Al-Obeid says his ministry plans to strengthen camel research, which is underway at several centers, including King Faisal University, where infectious-disease expert Abdulsalam Abdulan Bakhsh is investigating camel maladies.
Also, in January 2008, the newest phase of the Camel Breeding, Protection, and Improvement Center — built with help from the U.N.’s Food and Agriculture Organization — will open in northern Saudi Arabia.
… la relación entre las especies, subespecies … y demás, caimanes primos? sobrinos? gaviales tíos? nietos? … (éste es el más sonriente)
tan juguetón ahora, los ratones pueden convertirse rápidamente en machos agresivos.
(por aquí … los corzos?) ays.
más fotos: 
además:
