Confirming an Outbreak

Confirming that an epidemic is occurring is not always straightforward. In part, that is because clear definitions of outbreak thresholds do not exist for all diseases. For some diseases, a single case may indicate an outbreak. These include cholera, measles, yellow fever, shigella, and the viral hemorrhagic fevers.

General guidelines for meningococcal meningitis are that for populations >30,000, 15 cases/100,000 persons/week in 1 week indicates an outbreak. However, with a high outbreak risk (i.e., no outbreak for 3+ years and vaccination coverage <80%), this threshold is reduced to 10 cases/100,000 persons/week. In populations <30,000, an incidence of 5 cases in 1 week or a doubling of cases over a 3-week period confirms an outbreak.

For malaria, an increase in the number of cases above what is expected for the time of year among a defined population in a defined area may indicate an outbreak.¹

Post-Disaster Infectious Diseases

Following natural disasters, multiple factors increase the risk of contracting a communicable disease. These include inadequate sanitation, crowded conditions, food shortages, contaminated water, and inadequate immunization. Take all preventive measures possible and be alert for signs of potential epidemic diseases to avoid or quell a secondary disaster.

The diseases listed in Table 35-1 are common following disasters. All but tetanus have the potential of developing into epidemics. The best strategy is prevention, because adequate resources may not be available for treatment—or there may be no good treatment. Unfortunately, some preventive measures, such as hand washing, may not be easy to abide by in austere circumstances.

Conserve scarce resources for those who can benefit from them by limiting treatment to those who have a reasonable chance of surviving. The definition for “reasonable” depends on the amount of resources available in relation to the number of patients.

Immunizations

Individuals who are not used to giving intramuscular (IM) injections, including physicians, dentists, pharmacists, and emergency medical technicians (EMTs), may be needed to help during mass immunizations or for routine immunizations when trained personnel are scarce or busy elsewhere. As a reminder, IM injections and immunizations can be given in the lateral arm in the deltoid muscle; in the anterior thigh, especially with infants or struggling psychiatric patients; or in the upper outer-quadrant of either buttock (to avoid hitting the sciatic nerve). Do not give flu shots or rabies vaccine anywhere but in the arm. Administer as much rabies immune globulin as possible at the bite site and the rest in the arm that does not get the vaccine.

Cholera

Acidification of water rapidly kills Vibrio cholerae organisms. Adding the juice of one lime to a liter of drinking water rapidly kills Vibrio, although its efficacy depends on the type of lime. This technique has been successful in multiple locations around the world where the local limes’ pH is <2.5. In any cholera outbreak, it is prudent to first test the local limes’ ability (i.e., pH level) to kill Vibrio before suggesting this to the population.^4,5

Decontamination

Many diseases are transmitted through contact with body fluids, including hepatitis B virus, hepatitis C virus, and human immunodeficiency virus (HIV). Use hypochlorite concentrations ranging from 500 (1:100 dilution of household bleach) to 5000 ppm (1:10 dilution of household bleach) to clean spills of blood or body fluids such as cerebrospinal fluid and peritoneal fluid. The concentration depends on the amount of organic material that must be cleaned and the area to be disinfected. During Clostridium difficile outbreaks, disinfecting environmental surfaces with dilute sodium hypochlorite solutions (between 500 and 1600 ppm) effectively reduces the levels of environmental contamination.⁶

Stability of Hypochlorite (Bleach) Solutions

When 1:100-dilution hypochlorite solutions are stored in non-opaque spray or wash bottles, they retain 40% to 42% of their initial activity 30 days later. Solutions diluted 1:50 or 1:5 that are stored in closed brown opaque bottles retain their original activity at 30 days.

Either store hypochlorite solutions in sealed brown opaque bottles or prepare the initial hypochlorite dilutions at twice the final concentration of the chlorine level desired following 1 month of storage. For example, to have a solution containing 500 ppm of available chlorine on day 30, prepare an initial solution containing 1000 ppm of chlorine.⁶

Method to Preserve Possibly Infected Medical Records

The World Health Organization personnel developed a system to preserve the presumably infected medical records in treatment rooms for Ebola patients in West Africa. The system, which can be used in similar situations, is: Write the data on paper; then, when you leave, just before the sprayer begins disinfecting (“Show me your hands,” “Spread your fingers,” “Turn over your hands,” “Put your arms out”), somebody meets you with a camera phone and takes a picture of the paper with all its crucial data. They can also photograph the record through a window.

Infection Prevention Among Health Care Workers—Personal Hygiene

Hand Washing

Recent reports found that improved hand hygiene was associated with reduced health care–associated infections.⁷ However, hand washing may not be necessary before donning nonsterile gloves, because it does not decrease the already low bacterial counts on gloves—unless they are punctured with sharp instruments.⁸

When there are limited hand drying options, vigorously shake your hands 12 times. One folded paper towel or even a pants leg can finish the job.⁹

Emergency Medical Service Basic Hygiene Guidelines

Optimally, emergency medical service (EMS) personnel observe seven hygiene behaviors: (a) Disinfect hands with an alcohol-based hand cleaner before and after patient contact; (b) Correctly use gloves when faced with risk of contacting blood or other biological fluids; (c) Change gloves between treatment interventions; (d) Use gowns when there is risk of contact with blood or other biological fluids; (e) Wear short-sleeved uniforms when possible; (f) Do not wear rings, watches, or bracelets during patient care; and (g) Have short or tied-back hair.¹⁰

Fist Bump

Because of decreased surface area and time of contact, the fist bump, in place of a handshake, may further help reduce transmission of nosocomial infections in health care settings.¹¹

Surgical Hand Scrub

Two alternatives that exist for cleaning your hands before a surgical procedure are:

1. 
   

   Alcohol preparation

   
   
   
   
   1. 
      

      Wash hands and arms and clean fingernails; then dry them.

      
      
   2. 
      

      Apply alcohol solution containing emollient, rubbing until dry. Use approximately 3 to 5 mL per application; continue applications for approximately 5 minutes, using a total of 9 to 25 mL.

   
   
2. 
   

   Traditional 5-minute scrub with an agent containing chlorhexidine or an iodophor.

Homemade Soap

While soap is generally cheap and available, there may be times when you must make it. Here is a very basic recipe for hand soap:

• 
  

  ½ ounce (14 g) lye

  
  
• 
  

  ¼ cup cold water

  
  
• 
  

  ½ cup lukewarm fat

  
  
• 
  

  1 tablespoon lemon juice (optional)

In a plastic container, gently stir the lye into cold water with a wooden spoon. Slowly add lukewarm fat. Continue to stir until slightly thickened. Add lemon juice, stirring to mix thoroughly. Pour mixture into plastic molds. Cover with plastic wrap and leave for 24 hours. Remove soap from molds and allow to air dry for 14 days. This will make one to two medium-sized bars.

Homemade Hand Sanitizer

Either use 100% isopropyl alcohol as a hand sanitizer or make one that is a little gentler on the skin, using the formula below. In both cases, the active ingredient is alcohol, so use lotion on your hands to keep your skin from getting irritated. Put liquid in a small spray bottle or an old hand soap pump bottle and keep it on the counter.

• 
  

  1/3 cup aloe vera gel

  
  
• 
  

  2/3 cup 99% rubbing alcohol

  
  
• 
  

  Optional 8-10 drops essential oil (e.g., vanilla, lavender, grapefruit, peppermint, Thieves oil)

Mix ingredients. Use a funnel when pouring the mixture into a bottle.¹²

Additional Standard Precautions

Table 35-2 lists standard precautions to use when the necessary resources or improvised resources are available.

Syndromic Treatment

Clinicians use the constellation of patient-reported symptoms and observed physical signs to diagnose and treat patients. They often add imaging and laboratory testing, but these may not exist in austere situations. Therefore, clinicians have to go back to the basics, relying on their knowledge and experience. International medical groups call this “syndromic treatment.” In the old days, we called it good medical practice. The primary disadvantages of using this approach are overdiagnosis and overtreatment.¹³

Syndromic treatment regimens must be adapted to the local disease prevalence, antibiotic susceptibility, medication availability, and the patient’s ability to follow-up.

Exposure and Incubation Periods

A history of specific exposure, and the interval until disease onset, can often suggest the diagnosis, as illustrated in Table 35-3.