Tips for avoiding infectious disease

Everyone, at some point in their life, have experienced getting sick from another human being. Whether it was contracting chicken pox playing kickball in elementary school or kissing a significant other, it is not uncommon to contract an infectious disease from another person.

A disease is defined as an abnormal condition of an organism that impairs bodily functions, usually indicated by specific symptoms and signs. Infectious diseases, in particular, are caused by external factors such as viruses, bacteria, and other harmful pathogens. It may be as simple as the coughing of co-worker or carelessness in the hospital that can cause you to contract an infectious disease. These diseases range from the common cold to deadly sexually transmitted diseases.

Infectious diseases may seem like an omnipresent part of human life, but there are definitely steps that you can take to avoid contracting such infectious diseases. Being careful and conscious of your safety, along with knowing your surrounding environment can help you avoid contract an infectious disease. Your skin is the main defensive mechanism against infectious diseases, but some diseases will find other ways to enter your body.

The rest of this article will give you tips on how to avoid contracting infectious diseases. Follow these tips to change your behavior and avoid the spread and contraction of these diseases. Read more »

10 Tips to Prevent Infections

It may seem a daunting task to keep yourself and your loved ones free of infections. Beyond the obvious—steering clear of runny noses and hacking coughs—you may be wondering about some other practical ways of staying infection-free. Your skin acts as a natural barrier against harmful microbes that cause infections, but smart “bugs” have found alternative routes to get into your body and cause infection. By making a few simple behavioral changes (which ultimately reduce their access into your body), you can easily prevent the spread of many infectious diseases.

1. Wash your hands frequently. Did you know that microbes can live on inert surfaces anywhere from a few minutes to several months? Imagine these disease-causing microbes living on your computer keyboard, your light-switch, or even on the pedestrian-crossing button next to the crosswalk!Surprisingly, most people don’t know the best way to effectively wash their hands. The CDC recommends washing thoroughly and vigorously with soap and water for at least 20 seconds, followed by hand-drying with a paper towel. In the absence of running water, an alcohol-based hand gel or wipe will suffice, although nothing beats good ol’ soap and water. This takes about as long as it does to sing “Happy Birthday”, so some hospitals recommend washing your hands for the duration of this simple tune!
2. Don’t share personal items. Toothbrushes, towels, razors, handkerchiefs, and nail clippers can all be sources of infectious agents (bacteria, viruses, and fungi). In kindergarten, you were taught to share your toys, but keep your hands to yourself. Now try to remember to keep personal items to yourself as well!
3. Cover your mouth when you cough or sneeze. In a similar vein, good personal hygiene includes not only personal cleanliness, but also the age-old practice of covering your mouth when you cough or sneeze. Why is this important if you aren’t sick? For most infections, the disease-causing microbe has already started growing and dividing long before any symptoms begin to show. Coughing or sneezing can spread these germs through microscopic droplets in the air. The current recommendation is to cover your mouth with your arm, sleeve, or crook of the elbow, rather than using your hands. Read more »

Definition of Infectious Diseases

Infectious disease is disease caused by a pathogen which enters the body and triggers the development of an infection. Infectious diseases have a range of causes, and they can be found all over the world. These diseases are considered contagious or communicable, meaning that they can be passed from person to person. It is also possible for such diseases to spread indirectly through unhygienic conditions, or from animals to people, in which case they are known as zoonotic diseases.

A variety of pathogens can be responsible for infectious disease, including viruses, bacteria, fungi, protozoans, and prions. Within these large categories of infectious organisms, there are numerous modes of transmission and a colorful assortment of symptoms, although surprisingly few organisms cause infectious disease, when one considers the diversity of viral, bacterial, fungal, and protozoan life. In order to treat an infectious disease, doctors must be able to knock out the source of the infection and repair the damage it has done to the body. Many infectious diseases make the body vulnerable to secondary infections, in which other organisms move in to take advantage of a weakened immune system, and this can be very problematic.

The study of infectious disease is known as epidemiology. Epidemiologists work to determine the source of an infectious disease so that they can develop new treatment approaches. They also identify emerging outbreaks, which may develop into epidemics or pandemics, and areas where a disease is endemic, meaning that it occurs regularly. Malaria, for example, is endemic to some regions of Africa and Southeast Asia. Read more »

Male circumcision reduces risk of HIV transmission from women

In the study, published in the Feb. 15 issue of The Journal of Infectious Diseases, now available online, Jared Baeten and colleagues from the United States and Kenya collected detailed sexual data from a group of male Kenyan truckers and, using statistical models, developed infectivity measures that estimate the per-sexual-act probability of HIV transmission. The study is the first to calculate the probability of infection for men who have multiple, concurrent heterosexual partners, which was found to be significantly higher than infectivity rates calculated in the past from studies of monogamous couples. Their results may help explain the rapid spread of HIV in settings where circumcision is not common and multiple sexual partnerships are.

Between 1993 and 1997, 745 male employees of trucking companies based in Mombasa, Kenya were followed for the study. Initially they were evaluated for circumcision status and HIV-negativity. Over the length of the study the men were asked to give information concerning the number of sexual encounters with three different partner types–wives, casual partners, and prostitutes–and were screened for HIV and other sexually transmitted infections. At the end of the study the probability of infection was calculated using a statistical model that incorporated published data to estimate the rates of HIV infection among the three types of sexual partners.

For the men in the study, the overall probably of becoming HIV-infected following a single act of intercourse was calculated to be .0063, or one in 160. Uncircumcised men had a more than two-fold increased risk of infection per sexual act compared with circumcised men–one in 80 versus one in 200. Read more »

Typhus

Background

Typhus refers to a group of infectious diseases that are caused by rickettsial organisms and that result in an acute febrile illness. Arthropod vectors transmit the etiologic agents to humans. The principle diseases of this group are epidemic or louse-borne typhus and its recrudescent form known as Brill-Zinsser disease, murine typhus, and scrub typhus. (For more information on pediatric scrub typhus, see the eMedicine article Scrub Typhus in the Pediatric: General Medicine volume.)

Pathophysiology

Epidemic typhus is the prototypical infection of the typhus group of diseases, and the pathophysiology of this illness is representative of the entire category. The arthropod vector of epidemic typhus is the body louse (Pediculus corporis). This is the only vector of the typhus group in which humans are the usual host. Rickettsia prowazekii, which is the etiologic agent of typhus, lives in the alimentary tract of the louse. A Rickettsia- harboring louse bites a human to engage in a blood meal and causes a pruritic reaction on the host’s skin. The louse defecates as it eats; when the host scratches the site, the lice are crushed, and the Rickettsia- laden excrement is inoculated into the bite wound. The Rickettsia travel to the bloodstream and rickettsemia develops.

Rickettsia parasitize the endothelial cells of the small venous, arterial, and capillary vessels. The organisms proliferate and cause endothelial cellular enlargement with resultant multiorgan vasculitis. This process may cause thrombosis, and the deposition of leukocytes, macrophages, and platelets may result in small nodules. Thrombosis of supplying blood vessels may cause gangrene of the distal portions of the extremities, nose, ear lobes, and genitalia. This vasculitic process may also result in loss of intravascular colloid with subsequent hypovolemia and decreased tissue perfusion and, possibly, organ failure. Loss of electrolytes is common.

Some people with a history of typhus may develop a recrudescent type of typhus known as Brill-Zinsser disease. After a patient with typhus is treated with antibiotics and the disease appears to be cured, Rickettsia may linger in the body tissues. Months, years, or even decades after treatment, organisms may reemerge and cause a recurrence of typhus. How the Rickettsia organisms linger silently in a person and by what mechanism recrudescence is mediated are unknown. The presentation of Brill-Zinsser disease is less severe than epidemic typhus, and the associated mortality rate is much lower. Risk factors that may predispose to recrudescent typhus include improper or incomplete antibiotic therapy and malnutrition.

Murine typhus and scrub typhus share the same pathophysiology as epidemic typhus, although they are somewhat milder. The incubation period is approximately 12 days for the typhus group. Prior infection with Rickettsia typhi provides subsequent and long-lasting immunity to reinfection. Read more »