Nick received his B.S. in Biology from the University of Notre Dame and currently studies the spread of drug-resistant malaria.
Chlamydia is the most commonly reported sexually transmitted disease (STD) in the country, and cases have been increasing for decades. Though many cases of this bacterial infection are asymptomatic, chlamydia can cause long-term effects in both men and women. Women are particularly at risk for developing pelvic inflammatory disease and complications during pregnancy.
The burden of chlamydia is on the young, with almost two-thirds of cases affecting people aged 15-24. Thankfully, chlamydia is easily treatable with antibiotics and transmission risk is greatly reduced with safe sex practices. The CDC recommends annual chlamydia screening for sexually active women under 25 and men of at-risk populations. Unfortunately, the STDs syphilis and gonorrhea have also shown an uptick in recent years.
Ticks can carry a terrifying number of diseases. The CDC lists at least 15 of importance that are transmitted in the United States – caused by viruses, bacteria, and parasites. Three bacterial diseases in particular – anaplasmosis, erlichiosis, and Rocky Mountain spotted fever (RMSF) – seem to be on the rise lately, approaching one to two-thousand cases per year, up from only a few hundred a couple decades ago. All three diseases have symptoms that may include headache, fever, and rash, but presentation varies widely and may be asymptomatic. Final diagnoses can be laboratory-confirmed. Although all three can be deadly, case-fatality rates have fortunately dropped below 1-2% in recent years.
The burden of these diseases pales in comparison, however, to that caused by Lyme disease. Although the number of reported Lyme disease cases seems to have leveled off between 20,000-30,000 since 2002, the CDC estimates that the true number of people infected each year is closer to 300,000. Tick-borne diseases are expected to remain an important health concern in the U.S., especially as tick species increase their ranges, aided in part by climate change.
On the decline...
The viral hepatitides are caused by different viruses, but all result in inflammation of the liver. New cases of hepatitis A and B in particular have decreased in recent years due in large part to the development of vaccines. This finding underscores the importance of routine childhood vaccinations.
Meanwhile Hep C, discovered in 1989, still has no vaccine and after many years of decline new cases are actually increasing, especially in young mothers and their children. In 2013, Hep C killed more Americans than 60 other infectious diseases combined, including HIV and tuberculosis. This is because Hep C, along with Hep B, is a chronic disease, and the two viruses combined chronically infect up to 6 million Americans, many of whom do not even realize it. Still, new cases of Hep A and B are expected to continue to decline while we wait on a vaccine for Hep C. Interestingly, however, there is now a very effective cure for Hep C, though issues related to price hiking have been a hindrance to many patients around the world.
A century ago, rabies killed more than 100 people each year in the United States. Today, that number is down to just a few cases a year. Critical to that reduction was the elimination of domestic dogs as a rabies reservoir by mandating domestic animal vaccination. Today, dogs get infected the same way humans do: through exposure to wild animals.
A century ago, a rabies diagnosis was also a death sentence. However, 2004 marked the first documented case of a rabies survivor, which was accomplished through the use of the controversial Milwaukee Protocol, which involves putting the patient into a chemically-induced coma to give the body’s immune system time to fight the virus. As of 2013, there have been 2 more rabies survivors in the U.S., out of 23 documented cases. One survivor received Milwaukee Protocol treatment while the other did not. While a perfect cure for rabies remains elusive, the disease is not quite the killer that it once was, once again thanks to vaccination efforts. However, as long as the wildlife reservoir remains abundant, we should expect sporadic cases.
Healthcare-associated infections (HAIs)
These are infections that are acquired within the setting of a hospital. Although there are valid concerns about hospitals being breeding grounds for drug-resistant pathogens, a recent CDC report noted reductions in nearly all HAIs tracked from 2008 or 2011 to 2014. The report showed reductions of 50% in central line-associated bloodstream infections, 17% in surgical site infections, 8% in Clostridium difficile infections, and 13% in methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. While this shows progress in reducing HAIs, any infection acquired in a hospital as a result of treating a different condition feels like too many, especially as there are up to 75,000 people dying with HAIs each year. And while prevalence might be decreasing for now, antibiotic resistance is on the rise, cautioning healthcare providers everywhere to up their defenses even more.