A common misconception is that HIV and AIDS are the same thing, but HIV infection goes through multiple stages, with AIDS being the most advanced stage.

Stages and Symptoms

HIV progresses through 3 main stages: acute HIV infection, chronic HIV infection, and AIDS.

Acute HIV infection: 2-4 weeks after the virus enters the body; the virus rapidly proliferates throughout the body

• flu-like symptoms (fever, headache, sore throat)

• rash

• muscle aches

• swollen lymph nodes

• fatigue

• Some people experience no symptoms at all.

Chronic HIV infection: also known as clinical latency

• People may not experience any symptoms because the virus remains active but replicates at low levels.

• If untreated, this stage may last for years before progressing into AIDS

AIDS:

• People with AIDS are highly susceptible to opportunistic infections like pneumonia, tuberculosis, and certain cancers because HIV weakens the immune system.

• rapid weight loss

• recurring fever

• mouth sores

• diarrhea

Transmission

HIV is transmitted through direct contact with bodily fluids such as blood, semen, vaginal fluids, and breast milk. Examples include sexual intercourse, sharing needles, and transmission from mother to baby during pregnancy and breastfeeding.

Treatment

There is no cure for HIV, but it is treated with antiretroviral therapy (through pills or shots) to lower the levels of the virus in the body and help strengthen the body’s immune system.

Sources:

HIV.gov

Mayo Clinic

WHO

CDC

As a person gets older (65 and above), their risk of developing AD increases due to age-related changes in the brain that contribute to its onset.

Causes

A variety of factors contribute to AD, including family history (immediate family members of individuals with AD are at a higher risk of developing the disease themselves), genetics, lifestyle (e.g., smoking, poor diet, physical inactivity), and environmental influences.

At the neuronal level, Alzheimer’s disease is caused by the buildup of two types of proteins—amyloid plaques between neurons and tau tangles inside neurons—which lead to reduced neuronal communication and cell death.

Symptoms

Early signs of AD include:

• memory loss

• difficulty thinking, planning, or solving problems

• getting lost in familiar areas

• confusion with time or place

• problems with speaking or writing

• poor judgment

• mood or personality changes

As the disease progresses, symptoms may include:

• trouble controlling bladder/bowels

• changes in sleep patterns

• changes in personality or behavior

• changes in physical abilities (walking, sitting, swallowing)

• loss of verbal communication

Treatment

There is no cure for AD yet, so treatments focus on managing symptoms. For example, certain medications are able to improve cognitive function. Lifestyle changes like physical exercise, a balanced diet, and adequate sleep can support brain health and manage symptoms.

Alzheimer’s in History: Ronald Reagan

As the 40th President of the United States, Ronald Reagan achieved breakthroughs in foreign policy during the Cold War and implemented economic policies that spurred long-term growth. On November 5, 1994, Reagan (age 83) announced that he had been diagnosed with Alzheimer’s disease. Through a heartfelt letter to the American public, he hoped to promote greater awareness of AD and reduce the stigma surrounding the disease. Following his announcement, the Ronald and Nancy Reagan Research Institute was established in 1995 to accelerate funding, awareness, and research for Alzheimer’s. Today, Reagan is remembered as a transformational president whose leadership revitalized the national economy and restored American morale, and whose courage in sharing his diagnosis brought national attention to Alzheimer’s disease.

Sources:

Alzheimer's Association

UCSF

National Institute on Aging

Mayo Clinic

Cedars-Sinai

Reagan Library

Hoover Institution

History.com

Types of TB

Symptoms vary based on the type of TB a person has.

Inactive/Latent TB infection: TB germs are in the body, but the affected individual doesn’t have any symptoms and can’t spread TB to others because their immune system keeps the bacteria dormant. If left untreated, it can develop into active TB disease.

Active TB disease: The immune system can’t stop the TB germs from multiplying; symptoms can affect the lungs, kidneys, brain, spine, and skin:

• prolonged cough

• coughing up blood or mucus

• chest pain

• weakness/fatigue

• night sweats

• weight loss

• fever/chills

Treatment

TB can be treated and cured with antibiotics.

TB Throughout History

TB dates back to 9,000 years ago, with the first written descriptions originating in India and China. TB peaked in the 17th-19th century Europe and America, where it caused 25% of all deaths. Notable figures who contracted TB include George Orwell, English writer; Eleanor Roosevelt, former US first lady; and Frederic Chopin, Polish composer.

Today, TB remains one of the world’s deadliest infectious diseases, killing over 1 million people every year.

Sources:

CDC

Mayo Clinic

WHO

NLM

UC Health

Symptoms

Most people who get cholera have mild/no symptoms, but can still infect others if their stool contaminates food or water sources. For the few who do develop symptoms, they usually appear 2-3 days after getting infected and may include:

• watery diarrhea

• vomiting

• dehydration

• leg cramps

Treatment

Because cholera can cause death in just a few hours, treatment should be administered as soon as possible. Most people who get treated are able to recover successfully. Treatments include antibiotics, rehydration therapy (IV fluids or oral rehydration salts), and zinc supplements, which may help with cholera in children.

Cholera Throughout History

Cholera originated in India centuries ago and spread to other countries and continents through global trading networks. There have been seven major cholera pandemics throughout history, the first being in India in 1817. These pandemics have killed tens of millions of people, with the deadliest being the third pandemic. This pandemic spread through Asia, Europe, North America, and Africa, and killed 23,000 people in Great Britain alone in 1854. That same year, John Snow, a British physician, made the groundbreaking discovery that cholera was a waterborne disease, and he was able to trace and remove the source of the cholera outbreak in London. Today, we are currently undergoing the seventh cholera pandemic, which started in 1961 and continues to affect populations around the world (mainly communities with poor sanitation, inadequate hygiene, or unsafe drinking water).

Sources:

CDC

NLM

Mayo Clinic

History.com

WHO

Transmission

Syphilis spreads through direct skin-to-skin contact with a syphilis sore or rash, most often during sexual activity. Pregnant women with syphilis can also pass the infection to their baby (congenital syphilis).

Stages & Symptoms

Primary stage: usually 3 weeks after exposure

• a small, painless sore (some people get multiple) at the location where the bacteria entered your body (usually around the genitals, rectum, or mouth)

• usually lasts 3-6 weeks and heals on its own

• enlarged lymph nodes

• if left untreated, syphilis will progress to the second stage

Secondary stage: a few weeks after the original sore heals

• rough skin rash (commonly found on palms of hands or soles of feet)

• sores in the mouth or genitals

• headaches

• hair loss

• swollen lymph nodes

• weight loss

• fatigue

• muscle/joint pain

• symptoms can come and go for months or years; if left untreated, syphilis will progress

Latent stage: if you don’t get treated during the first two stages, the disease progresses to this stage

• no symptoms

• may last for years

• if left untreated, syphilis may start damaging your organs

Tertiary stage: 10-30 years after initial infection, though most people with untreated syphilis do not develop tertiary syphilis

• a range of health problems due to syphilis spreading to your internal organs:

  • nerve/brain damage

  • heart disease

  • seizures

  • paralysis

  • blindness

• can result in death

Treatment

Syphilis can be treated and cured with antibiotics (usually penicillin).

Syphilis in History: Tuskegee Syphilis Study

Officially titled “The Tuskegee Study of Untreated Syphilis in the Negro Male,” the Tuskegee Syphilis Study is considered one of the most unethical studies in the history of medical research. The goal of the study was to observe the natural course of untreated syphilis in African American men to document its long-term effects. Conducted between 1932 and 1972 by the U.S. Public Health Service, the study enrolled 399 Black men with syphilis and 201 uninfected Black men as a control group. Participants were told they were being treated for “bad blood” rather than being informed of their actual diagnosis. In addition, treatment was deliberately withheld from the participants, even after penicillin became a safe and widely available cure. The study was rooted in the “scientific racism” that was widespread during the early 1900s, which portrayed Black people as biologically inferior and undeserving of equal care. The Tuskegee Syphilis Study ultimately caused 128 men to die from untreated syphilis or related complications and resulted in infections in 40 wives and 19 children. It also contributed to a mistrust of the medical system among Black communities that persists to this day.

Sources:

CDC

Penn Medicine

Mayo Clinic

Cleveland Clinic

NHS Inform

NLM

McGill OSS

Cystinuria affects around 1 in 10,000 people.

Symptoms

• sharp pain in the lower back or abdomen

• fever

• vomiting

• bloody urine

Treatment

Treatments for cystinuria include increasing daily water intake, reducing salt and meat intake, and taking medication. These approaches all help reduce the risk of cystine stones forming.

Sources:

NLM

International Cystinuria Foundation

Medline Plus

Rare Diseases