Friday, October 31, 2014

'Toontime: Trick or Treat?

credit: Dave Grandlund
Wackydoodle sez: Do you give guarantees with that?
It is a small price to pay: staying around the house for three weeks, resting and recuperating from what must have been a very grim experience in the epidemic zone. Only politicians incurably addicted to self-aggrandizement would make a political football out of medical procedures intended to save lives and stop a pandemic from occurring. US Person finds it a little incredible that a three week quarantine at home would deter medical workers from helping in West Africa. This statistic would have that effect, however: 375 health care workers have been infected so far and Ebola has killed 211 according to the World Health Organization. This is a high death rate in spite of precautions taken by workers to protect themselves. Few studies have been done on the relative risks of infected blood, urine, vomit and other bodily fluids encountered by medics. In Uganda in 2001 researchers studied samples from 26 Ebola patients. In acute cases Ebola was found most often in saliva, but it was also found in stool, tears, blood and breast milk. One recovered patient had Ebola in his semen forty days after the disease onset! Results like these seem to indicate a fairly hardy organism. Corpses are perhaps the most infectious of all because fluids have a chance to mix and leak out. A single lapse in observing protocols could lead to an infection. In a recent 3 day training session at an Alabama army base, nearly every trainee committed a breach of protocol according to the CDC official in charge of the program.

credit: Michael Ramierz
BC Idonwanna: Buffalo soldier not under control!

The current Ebola epidemic in West Africa has two things in common with the HIV pandemic. Both viruses started out in animals inhabiting the same general region of tropical rainforest in southern Cameroon and neighboring countries. Ebola is thought to be endemic in fruit bats. Chimpanzees have a strain of virus (SIVcpz) that is genetically similar to HIV-1. The transmission of both viruses to humans occurred because human inhabitants hunt, butcher and consume both of these species. Bush meat, as it is commonly referred to, is a prized source of protein and even considered a delicacy. It is also responsible for transmitting disease.

A recent study based on phlyogeographic analysis of strains of HIV-1 DNA reported in Science (3 October 2014, P. Lemey et al) shows that the pandemic group (M) found throughout the world originated in Kinshasa, Zaire (DRG) around 1960. The virus probably arrived from southeast Cameroon via the colonial river trade in ivory and rubber by 1920. These strains first reached other Congo basin urban centers via Zaire's then operating rail network. By 1922 the railroads carried in excess of 300,000 passengers per year, peaking at more than a million in 1948. From these centers it was spread to the rest of sub-Saharan Africa. Subtype (B) commonly found in the Americas, arrived from Kinshasa with returning Haitian professionals who worked in the newly independent nation around 1964. HIV is transmitted through intimate contact with bodily fluids as is Ebola. Yet its spread throughout central Africa followed lines of transportation affecting the largest cities connected by rail first (Brazzaville 1937, Lubumbashi 1937 and Mbuji-Mayi 1939), and from these central African towns through international transport of exposed individuals to the rest of the world. The lesson for man is written in the viral DNA.