Hurricane Harvey Puts Health Officials on Alert for Water-Borne Infections

Hurricane Harvey continues to move at a snail’s pace across the South-Western states, bringing with it never-ending rains that have already contributed to flooding reaching as high as the roofs of some ranch homes, as of August 28, 2017. In addition to catastrophic damage and the displacement tens of thousands of individuals from their homes, the devastating floods have the potential to cause serious infectious diseases across the regions that have been affected. Several infections that can be caused because of flooding are listed below:

Typhoid Fever

This water-borne infection is caused by the bacterium Salmonella enterica serotype Typhi. The infection is common in areas where hand-washing is less frequent, or in areas where water has been contaminated by sewage, which is common in major flood areas. Although the infection is not common in the United States, Hurricane Harvey has brought with it major flooding that increases the risk of infection.

When the bacteria are ingested, they quickly reproduce and spread into the bloodstream. Symptoms of infection include a high fever, “103° to 104° F (39° to 40° C), weakness, stomach pains, headache, or loss of appetite. In some cases, patients have a rash of flat, rose-colored spots,” according to the Centers for Disease Control and Prevention (CDC). Once symptoms clear, an individual is still able to spread the disease and so treatment is imperative. Infection is confirmed via a stool sample. The CDC states that, “without therapy, the illness may last for 3 to 4 weeks and death rates range between 12% and 30%.” Antibiotics available to treat the infection include fluoroquinolones (for susceptible infections), ceftriaxone, and azithromycin.

Two vaccines against typhoid fever are available in the United States (Ty21a (Vivotif Berna, Swiss Serum and Vaccine Institute), and ViCPS (Typhim Vi, Pasteur Merieux)); however, individuals need to receive the vaccine at least 1-2 weeks prior to exposure (dependent upon vaccine type) so that the vaccine has time to take effect, according to the CDC.

Cholera and Other Vibrio Illnesses

Caused by the bacterium Vibrio cholera, cholera is an intestinal virus that causes acute diarrhea. Although, many times the infection is mild and does not cause any symptoms, in some cases, “profuse watery diarrhea, vomiting, and leg cramps,” can occur, according to the CDC. Like Salmonella enterica serotype Typhi, Vibrio cholera can be found in contaminated water. Treatment typically includes rehydration efforts and in severe cases, treatment with “doxycycline is recommended as first-line treatment for adults, while azithromycin is recommended as first-line treatment for children and pregnant women, according to the CDC.

Vibrio cholera is known to live in coastal waters and brackish rivers. Raw shellfish from the Gulf of Mexico have been found as a source of infection for many people in Gulf states, according to the CDC, and as a result, the Cholera and Other Vibrio Illness Surveillance System (COVIS) was created within the CDC. Other vibrio-related illnesses include infections caused by Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio alginolyticus, the 3 most common vibrio species in the United States.

Leptospirosis

Although incidence of leptospirosis is low in the United States, with the CDC reporting about 100-200 cases each year, 50% of which occur in Hawaii, flood waters in towns increase the risk of infection. The disease is caused by Leptospira bacteria, which are “long, thin, motile spirochetes,” that are spread through the urine of infected animals, according to the CDC. With an incubation period of about 7 days (range of 2 to 29 days), the clinical course for the infection is highly variable. According to the CDC, “symptoms include fever, headache, chills, muscle aches, vomiting, jaundice, anemia, and sometimes a rash;” and, although “the icteric form of the disease (Weil’s disease) is not common, hemorrhage, hepatomegaly, pulmonary hemorrhage, ARDS, and jaundice are among the severe features.” Antibiotics, such as doxycycline or penicillin, are usually administered as treatment for the infection.

Hepatitis A

Outbreaks of hepatitis A infections have made headlines across the United States this year, with cases occurring in San Diego, and last year, with a major outbreak linked with scallops in Hawaii, and additional outbreaks linked with frozen strawberries in multiple states. The highly-contagious liver infection occurs when an individual is infected with the hepatitis A virus. It is “usually transmitted by the fecal-oral route, either through person-to-person contact or consumption of contaminated food or water,” such as would occur during major flooding, according to the CDC. In addition, the CDC states that, “the clinical case definition for acute viral hepatitis is:

1. Discrete onset of symptoms (eg, nausea, anorexia, fever, malaise, or abdominal pain) and,
2. Jaundice or elevated serum aminotransferase levels.

Because the clinical characteristics are the same for all types of acute viral hepatitis, hepatitis A diagnosis must be confirmed by a positive serologic test for immunoglobulin M antibody to hepatitis A virus, or the case must meet the clinical case definition and occur in a person who has an epidemiologic link with a person who has laboratory-confirmed hepatitis A (ie, household or sexual contact with an infected person during the 15—50 days before the onset of symptoms).”

Although a vaccine against hepatitis A exists, those exposed to the virus (who have not previously received a vaccine) should “be administered a single dose of single-antigen hepatitis A vaccine or IG (0.02 mL/kg) as soon as possible, within 2 weeks after exposure,” according to the CDC. More information on the guidelines based on age and health status are available on the CDC website.

Hurricane Harvey flood victims are not only at increased risk of water-borne diseases; the risk of vector-borne diseases also increases in times of flooding. Check back on the Contagion® website tomorrow for information on the vector-borne infectious disease outbreak that can occur or be increased as a result of flooding.