Author Giovanni Battista Porta talks about wooden hearing aids that were carved into the shapes of ears belonging to animals with superior hearing. Wide at one end to gather sound, and narrow at the other end to direct amplified sound into the ear, early hearing aid trumpets were fashioned from animal horn, sea shell and glass. Later, common metals — such as copper and brass — were used. Trumpet-style hearing aids were shaped in various styles, depending on customer preference and degree of hearing loss.
HIV-1 from chimpanzees and gorillas to humans[ edit ] Scientists generally accept that the known strains or groups of HIV-1 are most closely related to the simian immunodeficiency viruses SIVs endemic in wild ape populations of West Central African forests.
Exactly when the zoonosis occurred is not known. Some molecular dating studies suggest that HIV-1 group M had its most recent common ancestor MRCA that is, started to spread in the human population in the early 20th century, probably between and Sample analyses resulted in little data due to the rarity of experimental material.
The researchers, however, were able to hypothesize a phylogeny from the gathered data. They were also able to use the molecular clock of a specific strain of HIV to determine the initial date of transmission, which is estimated to be around They all seem to derive from independent transmissions from sooty mangabeys to humans.
Groups C and D have been found in two people from Liberiagroups E and F have been discovered in two people from Sierra Leoneand groups G and H have been detected in two people from the Ivory Coast. These HIV-2 strains are probably dead-end infectionsand each of them is most closely related to SIVsmm strains from sooty mangabeys living in the same country where the human infection was found.
The resulting exposure to blood or other bodily fluids of the animal can result in SIV infection. Since rural Africans were not keen to pursue agricultural practices in the jungle, they turned to non-domesticated meat as their primary source of protein.
This over-exposure to bushmeat and malpractice of butchery increased blood-to-blood contact, which then increased the probability of transmission.
A study published in also discussed that bushmeat in other parts of the world, such as Argentina, may be a possible location for where the disease originated. The primary point of entry, according to researchers, is somewhere in the jungles of Argentina or Brazil. This suggests that the zoonotic transmission of the virus may have happened in this area.
However these relationships do not explain more detailed patterns of biogeography, such as why epidemic HIV-2 groups A and B only evolved in the Ivory Coastwhich is one of only six countries harboring the sooty mangabey.
All of them propose that the simultaneous epidemic emergences of four HIV groups in the late 19th-early 20th century, and the lack of previous known emergences, are explained by new factor s that appeared in the relevant African regions in that timeframe.
These new factor s would have acted either to increase human exposures to SIV, to help it to adapt to the human organism by mutation thus enhancing its between-humans transmissibilityor to cause an initial burst of transmissions crossing an epidemiological threshold, and therefore increasing the probability of continued spread.
Sharpand their colleagues proposed that "[the epidemic emergence of HIV] most likely reflects changes in population structure and behaviour in Africa during the 20th century and perhaps medical interventions that provided the opportunity for rapid human-to-human spread of the virus".
A largely masculine labor force was hastily recruited to work in fluvial and sea ports, railways, other infrastructures, and in plantations.
This disrupted traditional tribal values and favored casual sexual activity with an increased number of partners. In the nascent cities women felt relatively liberated from rural tribal rules  and many remained unmarried or divorced during long periods,   this being rare in African traditional societies.
Michael Worobey and colleagues observed that the growth of cities probably played a role in the epidemic emergence of HIV, since the phylogenetic dating of the two older strains of HIV-1 groups M and Osuggest that these viruses started to spread soon after the main Central African colonial cities were founded.In the s and early s, the outbreak of HIV and AIDS swept across the United States and rest of the world, though the disease originated decades earlier.
Today, more than 70 million people. HIV/AIDS & Asia and the Pacific In , 20 percent of the million new HIV infections worldwide were in southern Asia. HIV began its spread in Asia in the early to mids. In public health officials began to use the term "acquired immunodeficiency syndrome," or AIDS, to describe the occurrences of opportunistic infections, Kaposi's sarcoma (a kind of cancer), and Pneumocystis jirovecii pneumonia in previously healthy people.
Formal tracking (surveillance) of AIDS cases began that year in the United States. A brief history of hearing aids Today's tiny hearing aids are considered giants of modern technology, but they actually date back thousands of years.
A lot has changed about HIV/AIDS in the last 30+ years. Learn about the history of HIV/AIDS in the U.S. The Epidemic: A Global History of AIDS [Jonathan Engel] on caninariojana.com *FREE* shipping on qualifying offers.
From the Castro bathhouses to AZT and the denial of AIDS in South Africa, this sweeping look at AIDS covers the epidemic from all angles and across the world. Engel seamlessly weaves together science/5(10).