The incubation period or latency period is the amount of time between being exposed to a contagious disease and when you begin developing symptoms.
This is not the same as the contagious period or the time during which your child can get others sick.
Depending on the disease, the incubation period can be just a few hours or can last for several months. Knowing the incubation period for a disease can help you understand if your child is still at risk of getting sick or if he is in the clear — whether he is exposed to someone with strep throat, measles, or the flu.
“The incubation period is the time from exposure to the causative agent until the first symptoms develop and is characteristic for each disease agent.”
It can also help you figure out where and when your child got sick. For example, if your infant develops chickenpox, a vaccine-preventable disease, you can’t blame it on your cousin who doesn’t vaccinate her kids and who was visiting just three days ago. The incubation period for chickenpox is at least 10 to 21 days. So your child who is too young to be vaccinated likely caught chicken pox from someone he was exposed to a few weeks ago.
As we saw in recent outbreaks of Ebola and measles, a diseases incubation period can also help you figure out how long an exposed person needs to stay in quarantine. After all, if they don’t get sick once the incubation period is over, then they likely won’t get sick and can be released from quarantine.
Incubation Periods of Childhood Diseases
The incubation period for some common diseases includes:
Adenovirus – 2 to 14 days, leading to a sore throat, fever, and pink eye
vomiting after exposure to Bacillus cereus, a type of food poisoning – 30 minutes to 6 hours (short incubation period
Clostridium tetani (Tetanus) – 3 to 21 days
Chickenpox – 10 to 21 days
Epstein-Barr Virus Infections (Infectious Mononucleosis) – 30 to 50 days (long incubation period)
E. coli – 10 hours to 6 days (short incubation period)
E. coli O157:H7 – 1 to 8 days
Fifth disease – 4 to 21 days, with the classic ‘slapped cheek’ rash
Group A streptococcal (GAS) infection (strep throat) – 2 to 5 days
Group A streptococcal (GAS) infection (impetigo) – 7 to 10 days
Head lice (time for eggs to hatch) – 7 to 12 days
Herpes (cold sores) – 2 to 14 days
HIV – less than 1 year to over 15 years
Influenza (flu) – 1 to 4 days
Listeria monocytogenes (Listeriosis) – 1 day to 3 weeks, but can be as long as 2 months (long incubation period)
Mycoplasma penumoniae (walking pneumonia) – 1 to 4 weeks
Norovirus ( the ‘cruise ship’ diarrhea virus) – 12 to 48 hours
Pinworms – 1 to 2 months
Rabies – 4 to 6 weeks, but can last years (very long incubation period)
Respiratory Syncytial Virus (RSV) – 2 to 8 days
Rhinovirus (common cold) – 2 to 3 days, but may be up to 7 days
Roseola – about 9 to 10 days, leading to a few days of fever and then the classic rash once the fever breaks
Rotavirus – 1 to 3 days
gastrointestinal symptoms (diarrhea and vomiting) after exposure to Salmonella – 6 to 72 hours
Scabies – 4 to 6 weeks
Staphylococcus aureus – varies
Streptococcus pneumoniae (can cause pneumonia, meningitis, ear infections, and sinus infection, setc.) – 1 to 3 days
Whooping cough (pertussis) – 5 to 21 days
Knowing the incubation period of an illness isn’t always as helpful as it seems, though, as kids often have multiple exposures when kids around them are sick, especially if they are in school or daycare.
Conditions with long incubation periods can also fool you, as you might suspect a recent exposure, but it was really someone your child was around months ago.
Does your child get strep throat so often that you are thinking about getting his tonsils out?
While it is not uncommon for kids to get strep throat a few times a year once they are in school, it is even more common to get viral sore throats.
Strep throat, which can be treated with antibiotics, is caused by the group A Streptococcus (GAS) bacteria. And while a fast or rapid test can help determine if your child has strep throat or a virus, false positive (the test is positive, but the strep bacteria isn’t really making your child sick) results can sometimes confuse the picture.
Understanding Strep Throat
Before you can begin to understand why your child might be getting strep throat over and over again, you first have to understand strep throat and the current guidelines for diagnosing and treating strep.
“Diagnostic studies for GAS pharyngitis are not indicated for children less than 3 years old because acute rheumatic fever is rare in children less than 3 years old and the incidence of streptococcal pharyngitis and the classic presentation of streptococcal pharyngitis are uncommon in this age group.”
Infectious Diseases Society of America Guidelines
Strep throat is most common in children and teens between the ages of 5 and 15 years. While it might be possible for younger and older folks to get strep, especially if someone else in the house is sick with strep throat, since they aren’t considered to be at risk for acute rheumatic fever, it isn’t typically necessary to diagnose or treat them. It may surprise you, but strep throat does go away on its own – the main reason it is treated is so you don’t later develop rheumatic fever.
“Testing for GAS pharyngitis usually is not recommended for children or adults with acute pharyngitis with clinical and epidemiological features that strongly suggest a viral etiology (eg, cough, rhinorrhea, hoarseness, and oral ulcers).”
Infectious Diseases Society of America Guidelines
The classic symptoms of strep throat can include the sudden onset of a sore throat, fever, red and swollen tonsils (tonsillitis), possibly with white patches (exudate) and small, red spots (petechiae) on the roof of the child’s mouth, and tender, swollen lymph glands in their neck.
Kids with strep throat might also have nausea, vomiting, stomach pain, a headache, and a rash (scarlet fever).
Kids with strep throat will not usually have a cough, runny nose, hoarse voice, mouth ulcers, or pink eye with their sore throat. Those are symptoms that suggest a virus is causing the sore throat and they should not usually be tested for strep. This helps to avoid an unnecessary antibiotic prescription if your child tests positive, but really has a virus.
So basically, try to avoid over-testing for strep. But if your child does have strep throat symptoms and has a positive test, get an antibiotic that will clear the strep bacteria and finish all of your child’s prescription.
Avoiding Strep and Other Infections
Can you avoid getting strep?
As with other infections, the best way to avoid strep throat is to teach your kids to:
wash their hands properly
avoid close contact with people that are sick (for strep, that means until they have been on their antibiotic for at least 24 hours)
avoid drinking out of other people’s cups or glasses
consider taking a water bottle to school instead of drinking out of the water fountains
not touch their eyes or put objects (fingers, pencils, clothing, etc.) in their mouth, as that helps germs get in their body
cover their coughs and sneezes to avoid getting others sick
Most importantly, don’t wait until someone is sick in your home or lots of kids are getting sick at school to encourage your kids to avoid getting sick. By then, it will likely be too late.
Is Your Child a Strep Carrier?
If your child continues to get strep, especially if their strep test is always positive, it is likely time to consider that they may be a strep carrier.
“We recommend that clinicians caring for patients with recurrent episodes of pharyngitis associated with laboratory evidence of GAS pharyngitis consider that they may be experiencing >1 episode of bona fide streptococcal pharyngitis at close intervals, but they should also be alert to the possibility that the patient may actually be a chronic pharyngeal GAS carrier who is experiencing repeated viral infections.”
Infectious Diseases Society of America Guidelines
What does it mean to be a strep carrier?
It simply means that the strep bacteria are living or ‘hanging out’ in the back of your child’s throat. While that sounds bad, these strep bacteria aren’t causing any problems. They aren’t making your child sick, causing any symptoms, and don’t even make your child contagious.
“…the recovery of GAS does not establish causality. The tests do not distinguish carriage of GAS in a child with pharyngitis attributable to another cause from an acute infection caused by GAS.”
“Group A Streptococci Among School-Aged Children: Clinical Characteristics and the Carrier State” Pediatrics. 2004 Nov;114(5):1212-9.
The big problem with being a strep carrier is that whenever you have a strep test, these strep carrier bacteria will make the test positive, even if they aren’t what is causing your child’s symptoms.
This is often why people get diagnosed with strep and flu or strep and mono at the same time.
If you still don’t understand strep carriers, consider that if you go to almost any school and test every child, up to 20 to 25% of the kids will test positive for strep, even though they aren’t sick and have no symptoms. They are likely just strep carriers.
“We recommend that GAS carriers do not ordinarily justify efforts to identify them nor do they generally require antimicrobial therapy because GAS carriers are unlikely to spread GAS pharyngitis to their close contacts and are at little or no risk for developing suppurative or nonsuppurative complications (eg, acute rheumatic fever).”
Infectious Diseases Society of America Guidelines
What kind of efforts are they talking about? We sometimes hear about doctors ordering antibody tests, doing rapid strep tests and cultures on kids after they finish their antibiotics, testing everyone who lives in the house, or even testing the family dog.
None of this is usually necessary.
One thing that can be helpful is that if your pediatrician thinks that your child is a strep carrier, then instead of the more typical penicillin or amoxil antibiotics, they might treat your child with a stronger antibiotic, like clindamycin. This can help ‘knock out’ the carrier bacteria.
And then learn to be much more selective about getting strep tests, avoiding them if your child has more classic viral symptoms, like a cough and runny nose.
In addition to the idea of being a chronic carrier, there are other theories about why kids get recurrent strep throat infections, including:
antibiotic resistance – although this is thought to be rare or non-existent when it comes to the GAS bacteria and penicillin, amoxicillin, and cephalosporins. There is some resistance between azithromycin and strep, which is why it should only be prescribed if your child is allergic to the other antibiotics that are used to treat strep throat.
noncompliance – not finishing your antibiotic or not taking it as prescribed
influence of other bacteria – there are theories that other bacteria may be inactivating penicillin or amoxicillin (so you need a stronger antibiotic) or even that other beneficial bacteria help to kill the GAS bacteria, but may be gone if your child is frequently on antibiotics
you are starting antibiotics too quickly – some people think that if you don’t wait a few days and let the body start to fight the strep infection on its own, then it is more likely to come back
Or if your child had true strep throat symptoms, got well quickly after being on an antibiotic, but then got strep (with classic strep symptoms) again quickly, it is possible that it is just a new infection.
“We do not recommend tonsillectomy solely to reduce the frequency of GAS pharyngitis.”
Infectious Diseases Society of America Guidelines
If it is happening over and over again, consider the possibility that your child is a strep carrier and teach him or her how to avoid getting sick as much as possible.
Why not just get your child’s tonsils out? The problem is that many studies have shown that while this might help for a year or so, after that, these kids start getting strep just as much as they did before. So unless your child also has sleep apnea or has had complications of strep infections, like a peritonsillar abscess, you probably shouldn’t rush into a tonsillectomy.
What To Know About Recurrent Strep Throat Infections
Some other fast facts to know include that:
having tonsillitis does not automatically mean that your child has strep. Remember that viruses are an even more common cause of sore throats.
you can’t tell if someone has strep just by looking at their tonsils. Even having pus (white stuff) on their tonsils doesn’t automatically mean strep. Viruses can do that too. That’s why a rapid strep test, with a backup culture for negative tests, is important to make the diagnosis.
throwing out your child’s tooth brush every time they have strep isn’t necessary, after all, you don’t do that after they have other infections, do you? Instead, encourage your kids to routinely rinse their toothbrush after each use and replace it every 3 to 4 months.
Hopefully you have a better understanding of strep throat now.
Sore throat infections, including strep throat, are common, but remember to look for other answers besides just getting your child’s tonsils out if they get strep over and over.
Unfortunately, like most upper respiratory tract infections, the flu is not easy to treat.
What are Flu Symptoms?
While a cold and the flu can have similar symptoms, those symptoms are generally more intense and come on more quickly when you have the flu.
These flu symptoms can include the sudden onset of:
fever and chills
runny nose or stuffy nose
feelings of fatigue
And more rarely, vomiting and diarrhea.
In contrast, cold symptoms come on more gradually and are more likely to include sneezing, stuffy nose, sore throat, and mild to moderate coughing. A cold is also less likely to include a headache, fatigue, chills, or aches. And while either might have fever, it will be more low grade with a cold.
As with other infections, flu symptoms can be very variable. While some people might have a high fever, chills, body aches, constant coughing, and can hardly get out of bed, others might have a low grade fever and much milder symptoms.
That variability also applies to how long the flu symptoms might last. Some people are sick for a good 7 to 10 days, while others start to feel better in just a few days.
Treating Flu Symptoms
Although there aren’t many good treatments for the flu, that variability in flu symptoms makes it hard to even know if any you try really work.
For kids older than 4 to 6 years and adults, you could treat symptoms as necessary, including the use of decongestants and cough suppressants.
And of course, almost everyone might benefit from pain and fever relievers, drinking extra fluids, and rest, etc.
Treating the Flu
In addition to symptomatic flu treatments, there are also antiviral drugs that can actually help treat your flu infection.
These flu medications include oseltamivir (Tamiflu), zanmivir (Relenza), and peramivir (Rapivab). Of these, oral Tamiflu is the most commonly used. It can also be used to prevent the flu if taken before or soon after you are exposed to someone with the flu.
“If liquid Tamiflu is not available and you have capsules that give the right dose (30 mg, 45 mg or 75 mg), you may pull open the Tamiflu capsules and mix the powder with a small amount of sweetened liquid such as regular or sugar-free chocolate syrup. You don’t have to use chocolate syrup but thick, sweet liquids work best at covering up the taste of the medicine.”
FDA – Tamiflu: Consumer Questions and Answers
Unfortunately, these flu drugs are not like antibiotics you might take for a bacterial infection. You don’t take Tamiflu and begin to feel better in day or two. Instead, if you take it within 48 hours of the start of your flu symptoms, you might “shorten the duration of fever and illness symptoms, and may reduce the risk of complications from influenza.”
At best, you are likely only going to shorten your flu symptoms by less than a day. And considering the possible side effects of these medications and their cost, they are often reserved for high risk patients, including:
children who are less than 2 years old
adults who are at least 65 years old or older
anyone with chronic medical problems, including asthma, diabetes, seizures, muscular dystrophy, morbid obesity, immune system problems, and those receiving long-term aspirin therapy, etc.
pregnant and postpartum women
anyone who is hospitalized with the flu
anyone with severe flu symptoms
That means that most older children and teens who are otherwise healthy, but have the flu, don’t typically need a prescription for Tamiflu. The current recommendations don’t rule out treating these kids though.
“Antiviral treatment also can be considered for any previously healthy, symptomatic outpatient not at high risk with confirmed or suspected influenza on the basis of clinical judgment, if treatment can be initiated within 48 hours of illness onset.”
Antiviral Agents for the Treatment and Chemoprophylaxis of Influenza – Recommendations of the Advisory Committee on Immunization Practices (ACIP)
There is a lot of controversy surrounding the use of Tamiflu and other anti-viral flu medications, with some studies and many experts thinking that they should rarely be used, if ever, stating that they are not as useful as others claim. Others state that while they not perfect, they are all we have, and there is enough evidence to recommend their use.
Treating Hard to Control Flu Symptoms
Instead of learning about treating hard to control flu symptoms, which might require medical attention, it is probably much more important to learn how to recognize these severe flu symptoms that might be hard to control.
Your child’s flu might be getting worse and require quick medical attention if you notice:
fast or hard breathing
complaints of chest pain
that it is hard to wake up your child
irritability to the point that your child is not consolable
With a cough, wheezing, and trouble breathing that can linger for weeks, all RSV infections probably seem like they are hard to control, especially since up to 2% of kids, mostly high-risk infants, with RSV require hospitalization.
Still, it’s important to remember that for many kids, RSV is just a cold.
The first thing to understand about RSV is that it isn’t a disease.
Instead, RSV, or the respiratory syncytial virus, can cause many different kinds of upper and lower respiratory infections, ranging from the common cold and croup to bronchiolitis and viral pneumonia.
And almost all kids get sick with RSV at some point during the first few years of their life, especially if they are in daycare.
Fortunately, although RSV can cause life-threatening infections, especially in high-risk infants, the great majority of children get over their symptoms without any special treatments.
And infants who are the most high risk, including premature babies who were born at less than 29 weeks, can get five monthly doses of palivizumab (Synagis) during RSV reason to reduce their chances of getting sick. Infants with hemodynamically significant heart disease or chronic lung disease of prematurity can also get palivizumab.
Many of the classic treatments for RSV have now fallen out of favor with pediatricians. In fact, the American Academy of Pediatricians now advises against using albuterol breathing treatments, epinephrine, steroids, or chest physiotherapy (CPT) for infants with RSV bronchiolitis.
Not much, except pushing your child to drink and treating cold symptoms as possible.
The AAP even advises against routinely testing kids for RSV. That makes sense, since there is no treatment, kids can sometimes be contagious for 3 to 4 weeks, long after they have returned to daycare without symptoms, and other viruses can cause similar symptoms.
Instead, if your child has symptoms of RSV, especially if she was around someone else with RSV symptoms about two to eight days ago or is simply in daycare during RSV season (usually November to April), then it is safe to assume that your child has RSV.
Also understand that antibiotics have no role in the treatment of uncomplicated RSV infections. RSV is a virus. Antibiotics do not work against viral infections.
Going to Day Care with RSV
Since many kids who get RSV are in day care, the million dollar question often becomes, when can my child with RSV go back to day care?
“Most minor illnesses do not constitute a reason for excluding a child from child care, unless the illness prevents the child from participating in normal activities, as determined by the child care staff, or the illness requires a need for care that is greater than staff can provide.”
AAP Red Book 2015
Although I once had the manager of a day care argue with me that a child needed to test RSV negative before being allowed back into her day care, kids can usually go back, even if they still have cold symptoms, as long as they:
don’t have a fever for 24 hours
don’t have any trouble breathing
are not fussy or irritable
Since these kids will likely be contagious, the AAP recommends that “In child care centers, good hygiene practices should be used by the staff and the children, including frequent and thorough hand washing.”
Treating Hard to Control RSV
If your child has RSV symptoms and isn’t getting better, ask yourself these questions and bring the answers to your pediatrician or seek quick medical attention:
“Some youngsters with bronchiolitis may have to be hospitalized for treatment with oxygen. If your child is unable to drink because of rapid breathing, he may need to receive intravenous fluids.”
American Academy of Pediatrics
Do you think your child’s symptoms are hard to control, not because they are getting worse, but rather because they are lingering for several weeks, which can be normal when young kids have RSV?
Does your newborn or infant under two or three months have a fever (temperature at or above 100.4F/38C)?
Is your child having trouble breathing, such as breathing fast or hard, with chest retractions (chest caving in), nasal flaring, trouble catching his breath, or a non-stop, continuous cough?
Do you see any signs that your child isn’t getting enough oxygen, including that “his fingertips and the area around his lips may turn a bluish color?”
Is your child dehydrated, with less urine output, dry mouth, or no tears?
Does your child have any medical problems that put her at higher risk for a severe RSV infection, including extreme prematurity, having complex heart disease, chronic lung disease of prematurity, or immune system problems?
Is your child lethargic, which doesn’t simply mean that he is just playing less, but rather that he is actually hard to wake up and is maybe skipping feedings?
If your child with RSV is getting worse, although there aren’t any special treatments to make the RSV infection go away, supportive care is available to help your child through it, including IV fluids and supplemental oxygen. Those who are most sick sometimes end up on a ventilator to help them breath, and tragically, some infants with RSV die.
What To Know About Treating Hard to Control RSV
RSV is never really easy to control for infants and toddlers, as there is no treatment or cure, but fortunately, most kids do not have severe symptoms that require hospitalizations.
More Information About Treating Hard to Control RSV
Fifth disease, also called erythema infectiosum, is a very common viral infection that most kids get in early childhood.
It got its name because it was the fifth disease that was known to cause a fever and rash.
Measles was the first.
Symptoms of Fifth Disease
It is caused by parvovirus B19.
Symptoms start with a red rash on your child’s cheek, giving them the appearance that they have been slapped. And that’s where fifth disease’s other name comes from – slapped cheek disease.
This slapped cheek rash is often subtle, so that many parents might think that the rash is from the sun or wind. They often don’t even consider that their child might be ‘sick’ until a few days later, when they get a pink, lacy rash on their arms and legs. Even then, they might mistake the rash for hives, poison ivy, or any number of other common childhood rashes.
Diagnosis of Fifth Disease
Unless you understand that the fifth rash can come and go, being more obvious when your child is overheated, it can be easy to see why it isn’t quickly recognized by some people. It can also be confusing because the rash could also appear on a child’s back, chest, and leg – it doesn’t have to be limited to the cheeks and arms.
And the rash, which can be itchy, can linger for weeks or even months.
While a blood test can be done, it is this pattern of symptoms that makes the diagnosis.
Most importantly, understand that fifth disease eventually does goes away without treatment. While not usually necessary, anti-itch treatments may be tried.
Can your kids go to school with fifth disease?
Fortunately, kids are not contagious while they have this rash, so they can go to school and participate in other activities. You might need a note from your pediatrician to convince folks though. They were contagious during the week before they developed the rash though, so it can be a good idea to tell people, so they can look for symptoms too.
Facts About Fifth Disease
Other things to know about fifth disease include that:
Fifth disease is caused by the parvovirus B19 virus and is most common during the spring and school outbreaks are no uncommon.
The incubation period for fifth disease is very long – up to 4 to 21 days. That means you can get this virus about 4 to 21 days after being exposed to someone else that had it, especially if you were exposed to their respiratory secretions (coughing and sneezing) just before they developed their rash.
Prodromal symptoms of fifth disease, which can start 7 to 10 days before the rash, might include a few days of mild fever, muscle aches, headache and decreased activity.
In addition to a rash, adults with fifth disease can also have joint pain and arthritis.
It is also important to know that like roseola, fifth disease can be more serious for those with immune system problems. It can also be serious for pregnant women who aren’t immune and for those with hemolytic anemia and sickle cell disease.
What to Know About Fifth Disease
Fifth disease is a very common viral infection that causes a characteristic rash on a child’s cheeks, arms, and legs that can linger for weeks.
It was first described in the journal Pediatrics in 1910 by J. Zahorsky.
Also called roseola infantum or exanthem subitum (sixth disease), it is caused by human herpes virus type 6 and 7. That fact wasn’t discovered until 1986 though.
Roseola is best known for causing a high fever for about three to five days, but even more characteristically, roseola often causes a rose-pink or red rash on your child’s trunk once the fever breaks.
Infections can also be asymptomatic.
There are no treatments and it rarely causes complications. Even febrile seizures that can be triggered by roseola, which happens commonly, are not thought to be serious.
Roseola, even reactivation of an old infection, can be a serious for children or adults with immune system problems though, especially those who have had a stem cell transplant.
What To Know About Roseola
Roseola is a common viral infection that most kids get in early childhood. The biggest problem when having roseola is that by the time you get diagnosed, because the fever is gone and your child has a rash, it is basically over.