With three months left in 2013, the Southern Nevada Health District reports there have already been 19 more cases of potentially fatal whooping cough, or pertussis, in Southern Nevada than the 83 experienced all of last year.
The 102 cases in Clark County is the highest since 1991, when statewide electronic records began to be kept, according to Linda Verchik, a disease surveillance supervisor with the health district’s office of epidemiology.
Statewide, the number of cases midway through September stands at 138, 46 more than in 2012 and 104 more than in 2011.
Verchik said the reason for Nevada’s increase is unknown, but authorities believe it is partially because of more active surveillance. She said Nevada health officials now even monitor tests for the disease in an effort to keep the disease from spreading.
“We can’t explain it (the increase),” she said. “We’ve been working hard to get children immunized in school and in child-care facilities.”
Not all cases of whooping cough get reported, health officials say, often running their course naturally.
Despite the rise of the disease in Nevada — federal officials say a rise and fall of the disease in various states is commonplace — it is far less than the more than 2,000 already suffered in Texas, a fact state officials partially attribute to educational efforts that involve both medical practitioners and the public.
Nationwide, nearly 16,000 provisional whooping cough cases have been reported to the Centers for Disease Control and Prevention as of Sept. 15. According to the CDC, overall reporting of the disease has declined this year. Although 13 states, including Nevada, have reported an increase in pertussis cases compared with the same time during 2012, the majority of states have reported fewer cases in 2013 to date. There were nearly 42,000 cases reported in 2012, the worst year for whooping cough in six decades.
A highly contagious, vaccine-preventable bacterial disease, whooping cough starts with mild coldlike symptoms then develops into severe coughing fits that produce a “whoop” sound in infected babies when they inhale air after coughing. Caused by bacterium called Bordetella pertussis, which is found in the mouth, nose and throat of the person infected with the disease, pertussis is spread through the air by infectious respiratory droplets.
No deaths have been reported in Nevada. Texas public health officials reported two deaths there.
Pertussis is generally treated with antibiotics, which are used to control symptoms and prevent infected people from spreading the disease.
The most dangerous cases are those found in infants less than 12 months of age. Whooping cough can lead to other serious complications, including pneumonia. In recent years, about 92 percent of pertussis deaths have occurred in infants younger than 12 months of age.
Babies are particularly vulnerable because they don’t start receiving their own immunizations against pertussis until they are 2 months old and are not fully protected until they’ve had at least three doses of the infant DTaP (diphtheria, tetanus and acellular pertussis) vaccine.
Verchik said that children attending school in Clark County must be immunized before they can attend kindergarten and before entering the seventh grade. Older children and adults, including adults older than 65, should receive Tdap boosters that contain protection against tetanus, diphtheria and pertussis in place of their next tetanus shot.
It is recommended that pregnant women be vaccinated with Tdap after reaching 20 weeks gestation.
That Nevada’s number of whooping cough cases continues to be low may be because of the state’s emphasis on “cocooning,” Verchik said. What that means is that all family members and close contacts of the family are protected from the disease because of immunizations and cannot give a vulnerable infant pertussis.
Over the past several years, Nevada public health officials have urged pediatricians, public health officials and hospitals to work together to notify families and their friends and their caregivers about getting immunized before a child is born.
The CDC reports overall reporting of pertussis has declined during 2013. While 13 states and Washington, D.C., have reported an increase in pertussis cases compared with the same time during 2012, the majority of states have reported fewer cases in 2013 to-date.
Before a vaccine was introduced in the 1940s in the United States, whooping cough was a feared childhood killer in the 1920s and 1930s, with about 9,000 deaths out of about 250,000 cases per year.