William Henry Welch (April 8, 1850 – April 30, 1934) was an American physician, pathologist, bacteriologist, and medical-school administrator. He was one of the "Big Four" founding professors at the Johns Hopkins Hospital. He was the first dean of the Johns Hopkins School of Medicine and was also the founder of the Johns Hopkins School of Hygiene and Public Health, the first school of public health in the country. Welch was more known for his cogent summations of current scientific work, than his own scientific research. The Johns Hopkins medical school library is also named after Welch. In his lifetime, he was called the "Dean of American Medicine" and received various awards and honors throughout his lifetime and posthumously.
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- ⭐ Core Definition: William H. Welch
- William H. Welch in the context of Plasmodium falciparum
- William H. Welch in the context of Clostridium perfringens
William H. Welch in the context of Plasmodium falciparum
Plasmodium falciparum is a unicellular protozoan parasite of humans and is the deadliest species of Plasmodium that causes malaria in humans. The parasite is transmitted through the bite of a female Anopheles mosquito and causes the disease's most dangerous form, falciparum malaria. P. falciparum is therefore regarded as the deadliest parasite in humans. It is also associated with the development of blood cancer (Burkitt's lymphoma) and is classified as a Group 2A (probable) carcinogen.
The species originated from the malarial parasite Laverania found in gorillas, around 10,000 years ago. Alphonse Laveran was the first to identify the parasite in 1880, and named it Oscillaria malariae. Ronald Ross discovered its transmission by mosquito in 1897. Giovanni Battista Grassi elucidated the complete transmission from a female anopheline mosquito to humans in 1898. In 1897, William H. Welch created the name Plasmodium falciparum, which ICZN formally adopted in 1954. P. falciparum assumes several different forms during its life cycle. The human-infective stage are sporozoites from the salivary gland of a mosquito. The sporozoites grow and multiply in the liver to become merozoites. These merozoites invade the erythrocytes (red blood cells) to form trophozoites, schizonts and gametocytes, during which the symptoms of malaria are produced. In the mosquito, the gametocytes undergo sexual reproduction to a zygote, which turns into ookinete. Ookinete forms oocytes from which sporozoites are formed.
View the full Wikipedia page for Plasmodium falciparumWilliam H. Welch in the context of Clostridium perfringens
Clostridium perfringens was discovered in 1891 by Dr. William H. Welch. It was originally known as Bacillus aerogenes capsulatus, followed by Bacillus welchii, before the final establishment of its current name. C. perfringens is a Gram-positive, bacillus (rod-shaped), anaerobic, spore-forming pathogenic bacterium of the genus Clostridium. C. perfringens is present in nature and can be found as a normal component of decaying vegetation, marine sediment, the intestinal tract of humans and other vertebrates, insects, and soil. It has the shortest reported generation time of any organism at 6.3 minutes in thioglycolate medium.
Clostridium perfringens is one of the most common causes of food poisoning in the United States, alongside norovirus, Salmonella, Campylobacter, and Staphylococcus aureus. However, it can sometimes be ingested and cause no harm.
View the full Wikipedia page for Clostridium perfringens