42. How did Louis Pasteur demonstrate publicly his discovery to
anthrax ?
Answers
Answer:
Louis pasteur demonstrated publicly his discovery to anthrax by Braille Script
Anthrax. Robert Koch is widely known for his work with anthrax, discovering the causative agent of the fatal disease to be Bacillus anthracis. He discovered the formation of spores in anthrax bacteria, which could remain dormant under specific conditions.
Born: 11 December 1843, Clausthal-Zellerfeld
Died: 27 May 1910, Baden-Baden
Medical specialty: Microbiology
Vaccines against the livestock and human disease anthrax—caused by the bacterium Bacillus anthracis—have had a prominent place in the history of medicine, from Pasteur’s pioneering 19th-century work with cattle (the first effective bacterial vaccine and the second effective vaccine ever) to the controversial late 20th century use of a modern product to protect American troops against the use of anthrax in biological warfare. Human anthrax vaccines were developed by the Soviet Union in the late 1930s and in the US and UK in the 1950s. The current vaccine approved by the U.S. Food and Drug Administration (FDA) was formulated in the 1960s.
Currently administered human anthrax vaccines include acellular (USA, UK) and live spore (Russia) varieties. All currently used anthrax vaccines show considerable local and general reactogenicity (erythema, induration, soreness, fever) and serious adverse reactions occur in about 1% of recipients.New third-generation vaccines being researched include recombinant live vaccines and recombinant sub-unit vaccines
. The disease and its importance
The natural disease
Anthrax is primarily a disease of herbivores.
Humans almost invariably contract the natural disease directly or indirectly from animals or animal
products.
Deliberate release
Bacillus anthracis has always been high on the list of
potential agents with respect to biological warfare
and bioterrorism. It has been used in that context on
at least two occasions, prepared for use on several
other occasions and been the named agent in many
threats and hoaxes.
2. Etiology and ecology
Etiology
Anthrax is caused by the bacterium Bacillus anthracis.
Cycle of infection
The infected host sheds the vegetative bacilli onto
the ground and these sporulate on exposure to the
air. The spores, which can persist in soil for decades,
wait to be taken up by another host, when germination and multiplication can again take place upon
infection. Flies appear to play an important role in
large outbreaks in endemic areas.
Humans acquire anthrax from handling carcasses, hides, bones, etc. from animals that died of
the disease.
Influencing factors
The cycle of infection is influenced by (i) factors that
affect sporulation and germination, such as pH,
temperature, water activity and cation levels; and
(ii) factors related to the season, such as available
grazing, the health of the host, insect populations
and human activities.
3. Anthrax in animals
Infectious dose in animals
LD50s range from < 10 spores in susceptible herbivores to > 107
spores in more resistant species when
administered parenterally. However, B. anthracis is not
an invasive organism and by inhalational or ingestion routes, LD50s are in the order of tens of thousands, even in species regarded as susceptible. The
relationship between experimentally determined
LD50s and doses encountered by animals acquiring
the disease naturally is poorly defined.
Global incidence in animals
National programmes have resulted in a global
reduction of anthrax, although this is counteracted
by the failure of more recent generations of veterinarians, farmers, etc., through lack of experience,
to recognize and report the disease, and the abandonment of vaccination. The disease is still common
in some Mediterranean countries, in small pockets
in Canada and the USA, certain countries of central and South America and central Asia, several
sub-Saharan African countries and western China.
Sporadic cases and outbreaks continue to occur elsewhere.
Transmission in animals
• It is a long-held belief that animals generally
acquire anthrax by ingestion of spores while grazing or browsing. However, anomalies in the epizootiology of the disease often arise that are hard to
explain in terms of simple ingestion of spores.
• Flies appear to play an important role in explosive
outbreaks.
• Inhalation within dust may be important on occasion.
• Direct animal-to-animal transmission is believed
to occur to an insignificant extent, excluding carnivores feeding on other victims of the disease.
• Human activities in the form of trade have long