Streptococcal pharyngitis is a throat infection which is commonly known as strep throat. This is a bacterial infection which is caused by Streptococcus pyogenes (group A Streptococcus), commonly abbreviated as GAS.
What makes this infection particularly important is that it can easily be transmitted from one person to another.
While many of the readers may be troubled by the question “Is strep throat contagious?”, let us list here all the details you need about this disease.
Yes, strep throat is contagious in nature and once you have it you have to be careful as you definitely do not want your family or friends to get your infection.
According to Centers of Disease Control and Prevention (CDC), strep throat is the most common reason for sore throat in children, whereas in adults it is relatively less common.
Is Strep Throat Contagious? What Causes Step Throat?
- Strep throat is caused by streptococcus pyogenes — a gram positive bacteria.
As we mentioned earlier, it is a bacterial infection involving the pathogen Streptococcus pyogenes. Group A streptococci (GAS) belong to the extracellular gram-positive genus which are causative agents for not only strep throat but also for impetigo, skin infection characterized by red sores, acute glomerulonephritis (inflammation of glomeruli) and rheumatic fever. The bacteria colonize in the throat or skin leading towards suppurative (pus formation) infection and non-suppurative continuation of previous infection.
- ‘Is strep throat contagious?’ should not be ambiguous anymore, as its contagious nature is evident from its wide spread. Its reach includes all ages and it leaves no places untouched.
Affecting majorly the children between the age of 5 to 15 years, people of all ages are susceptible to contracting this infection in a crowded place. Often places like crowded schools, offices and military facilities are the breeding grounds for the spread of strep throat from one person to the other.
The bacterial cells begin to colonize the throat by adhering to the dermal epithelial cells or pharyngeal cells. This adherence is a result of bacterial surface ligand binding with specific receptors on the host cells. This strong adherence mechanism is an important factor due to which strep throat is common and its causative agent doesn’t get washed away easily.
As salivary fluid and mucous passing down the mouth could not counteract the bacterial adherence, the bacteria are not swiped away and they continue to cause damage to the tissues in the throat.
If we talk of skin attachment and group A streptococci colonization, it is crucial to understand that a previous exposure to the bacteria leads to overcoming of dermal barriers and facilitate bacterial cell adherence to the host cells. Investigations have also shown that at specific sites the normal flora is in competition with the bacterial cells for adherence to the host cells.
Further investigation into the adherence and colonization of streptococci is thereby of an integral value for the formulation of anti-adhesive therapies and vaccination for streptococcal infection prevention and/or treatment.
How Long Is Strep Throat Contagious?
If you suffer from strep throat, you might be worrying a lot for the people around you. But, let’s ease your worry here and help you understand for how long you can be a threat to your loved ones. While the answer to your question “is strep throat contagious?” is a yes, you can feel relieved to know that the contagion factor reduces drastically once you are on medication.
- Strep contagion is tricky because it attacks when the bacteria bearer is not experiencing the symptoms of his disease. Surprisingly, strep throat is contagious in between 2 to 5 days prior to the exhibition of symptoms.
As streptococcus pyogenes belong to Group A streptococcus infection, the time period for GAS to be contagious is between 2 to 5 days before you start to show your symptoms. This is the tricky part: now that you are a carrier of a disease without having symptoms, you are unaware of the fact that you are transferring germs to your family or friends around you.
Over the course of next few days, when you start to manifest strep throat symptoms, you have to limit your contact with friends and family so that you are not shedding out bacteria which is making other people sick.
Similarly, if you are not taking antibiotics for strep throat, you can be contagious for about 2-3 weeks. On the other hand, if you have started taking antibiotics for your bacterial infection, then you are not contagious 24 hours after taking the first dose of antibiotic treatment.
How Do You Get Strep Throat? Is Strep Throat Contagious?
Caused by a contagious bacterial strain, GAS lives in your throat and nose which can spread easily to uninfected people around you. The bacteria travel through small respiratory droplets. You can contract this infection if you breathe in droplets that carry the germs or if you touch something which has the droplets on it and then you touch your nose or mouth with your contaminated hands.
Similarly, if you share a glass or a plate with a sick person, you are at a high probability of getting infected. At other times, if you touch skin sores caused by GAS, often in the case of impetigo, you are likely to get infected.
Rarely, you can catch GAS from food if it is not properly handled. Yes, the infection can be Foodborne as well, though that doesn’t happen often. Before pasteurization, preservation, and refrigeration of food became common, the Foodborne cases of GAS spread were seen commonly. The GAS pharyngitis, aka strep throat, outbreak used to happen due to food contamination and the consumption of raw milk.
The detection of Foodborne outbreaks of strep throat is hard now but if a cluster of people come with a complaint of sore throat from one venue, it can hint at the bacteria-contaminated food.
As reported by the Oxford Journal of Clinical Infectious Disease, on 20th March, 2012, the Minnesota Department of Health was notified on social media sites, suggesting a Foodborne outbreak of GAS pharyngitis at a high school dance banquet. Upon investigation and laboratory testing of food specimen, it was found that out of 63 party attendees, 18 people fell ill after eating pasta.
Later, GAS colonies were isolated from the patients and leftover pasta which confirmed the link. The investigators found that the pasta was prepared by an attendee who was ill with strep throat 3 weeks earlier, along with both the parents. It was concluded that the pasta prepared by people who previously fell sick by the bacteria was the prime facilitator (mode of transmission) of bacterial spread.
Signs And Symptoms Of Strep Throat In Children
Strep throat is more common in children than in adults. Reportedly, 4 to 6 out of every 20 children with the complaint of sore throat suffer from strep throat. In adults the ratio comes down to 1 to 3 persons in a group of 20 people.
Symptoms of strep throat in children include:
- Sore throat
- Red, swollen tonsils
- Yellow/white patches on the tonsils and in the throat
- Difficulty in swallowing food
- Nasal congestion
- Pain in muscles
- Abdominal pain
- Neck pain
- Nausea and vomiting
- Loss of appetite
- “Strawberry” tongue – a term used for red and inflamed taste buds
- Joint stiffness
- Swollen lymph nodes in neck
Signs And Symptoms Of Strep Throat In Adults
After entering your system, the bacterial incubation time is between 1 to 5 days. You should be careful of your surroundings to be sure that your symptoms are indicative of strep throat. If you have sore throat and fever or know somebody already infected around you, you should get the first hint.
After a few days when incubation period of the bacteria has ended, you will begin to show some or all of the signs and symptoms of strep throat which include:
- Sore throat
- Fever which is often greater than 102oF
- Yellow or white tinted pus area in the throat or on the tonsils
- Pain in the muscles
- Runny nose
- Consistent sneezing
- Swollen lymph nodes in the neck
- Rarely you may develop rash on skin (this condition is known as scarlet fever)
However, the CDC suggests that hoarseness in the voice, cough, runny nose and pink eye (conjunctivitis) are not the symptoms of strep throat and the presence of these symptoms indicates viral infection.
Diagnosis Of Strep Throat
Differentiating strep throat from other infections marked with sore throat is important so that the right treatment can be given to the patient. Often the symptoms overlap with other viral infections, leading to wrong medication prescriptions. For diagnosing strep throat, two commonly used tests include:
- A rapid strep test
- A throat culture test
Rapid Strep Test:
The throat is swabbed and this swab sample is taken to the laboratory for the identification of pathogens. If the test is possible for GAS, then antibiotic therapy is prescribed.
In case this rapid test is negative and the doctor suspects the infection to have been caused by streptococcus A bacterium, a throat culture swab is carried out to minutely monitor bacterial growth in the sample.
Throat Culture Test:
It is worth noting that carrying out the throat culture test is not important in adults. In children it is better to carry out a throat culture test and wait for the results to be sure of the nature of infection.
It is important in the case of children because they are highly susceptible to developing rheumatic fever if the strep throat infection remains untreated by antibiotic therapy.
In additional to these routine tests, Antistreptolysin O Titer test may also be ordered by your doctor to know if you have had been suffering from strep infection with group A streptococcus in the recent past.
This test can be carried out along with anti-DNase B test that also helps in the detection of strep A infection. These tests, however, do not diagnose strep throat, but help in identifying strep bacteria as the cause of advanced infection like kidney inflammation, glomerulonephritis or rheumatic fever.
Strains Of Streptococcal Bacteria Responsible For Strep Throat
Streptococcal infections at large can contribute towards a variety of infections ranging from mild throat infections to severe infections of organs or blood which can be life threatening in nature. This bacterial genus can be divided into three categories which can give rise to different infections. These categories of streptococcal bacteria include group A, B and D streptococci.
Streptococcus Group A:
As we talked earlier, this bacterium is responsible for causing strep throat. However, it is also associated with causing other infections. Some of these infections include:
- Cellulitis: an infection of deeper layers of the skin which can lead to affected areas to become painful, hot, red and swollen.
- Impetigo: a skin infection characterized by blister, sores and crusts.
- Sinusitis: an infection of cavities behind cheekbones and forehead leading towards throbbing pain in face in addition to a blocked or runny nose.
- Middle ear infection: it is characterized by temporary hearing loss, high degree fever and earache.
- Scarlet fever: it is accompanied by pink-red rashes all over the skin.
In rare cases, the bacteria can penetrate into the tissues and organs to cause invasive strep A infections. These rare infections are commonly in certain groups of people, including people with weakened immunity, diabetes patients, HIV/AIDS patients, older adults and babies. These infections include:
- Toxic shock syndrome, in which bacteria release toxins in the bloodstream and cause high degree fever, vomiting, fainting, diarrhea and dizziness.
- Necrotizing fasciitis: an infection in the deep skin layers, covering of muscles and fats leading towards pain, redness of affected area and swelling.
Streptococcus Group B:
This group of bacteria often lives harmlessly in the vagina of women and the digestive system of individuals. Streptococcus group B bacteria can particularly affect pregnant women and newborn babies, however the cases remain rare and according to National Health Services, England, most babies who are exposed to strep B at the time of birth remain unaffected and only 1 in every 2,000 cases get infected.
It is also a cause of invasive infections in older adults who suffer from a chronic medical condition like heart disease or type 2 diabetes.
The infections associated with strep B bacteria include:
- Urinary tract infections
- Blood infections
- Bone infections
- Skin infections
The bacteria is said to live in the intestine, rectal area and vagina in about a quarter of healthy population. It is a gram-positive bacteria, also known as Sreptoccocus agalactiae and should not be confused with strep throat causing pathogen which belongs to group A streptococcus.
In a recent report released by the CDC, group B streptococcus based Foodborne outbreak was recorded in Singapore in 2015. The infection was associated with the consumption of raw fish. Presented in a Chinese-style raw fish dish (yusheng), eating it resulted in bacteremia (blood infection) in 40 people. Other lesser cases of septic arthritis, bacteremia complicated by meningitis and epidural space abscess were also found.
Streptococcus Group D:
This group is often associated with infections of blood, known popularly as bacteremia which can sometimes be accompanied with another infection of the endocardial surface of the heart (endocarditis). Endocarditis can further include involve heart valves, mural endocardium (lining of heart chamber walls) or cause a septal defect. These infections can lead to heart failure or a suppurative infection of myocardium known as myocardial abscess.
Other rarely streptococcus group D associated infections include:
- Urinary tract infections
- Spontaneous bacterial peritonitis, meningitis
- Neonatal sepsis, septic arthritis
- Vertebral osteomyelitis
Difference Between Strep Throat, Sore Throat And Tonsillitis
It is often hard to be sure if you suffer from strep throat. The symptoms of a scratchy throat, unpleasant or painful throat condition are not only the symptoms of strep throat but they can also arise as a result of multiple throat infections or problems.
For instance, the irritation in the throat, commonly known to us as sore throat, can be due to various bacteria or viruses which are responsible for conditions other than strep throat, pollutants, allergens, fungal infection or chronic postnatal drip. Therefore, it is very important for you and your physician to be certain that you are suffering from strep throat so that appropriate antibiotics can be prescribed.
In this context, it is important to differentiate between strep throat, sore throat and tonsillitis. In a layman’s language, these three terms are interchangeable but in reality, they are not the same thing.
Strep throat is an infection caused specifically by the streptococcus pyogenes and its symptoms can vary depending on the person’s age. People tend to mix strep throat with tonsillitis because strep throat is accompanied with inflammation of tonsils. What needs to be realized here is that it is not just the inflammation of tonsils which takes place in strep throat, this condition is also marked by inflammation of surrounding areas of throat.
- In strep throat inflammation of tonsils and surrounding area are observed.
Tonsillitis is marked with the inflammation of tonsils due to infection. Tonsils are the lymph nodes located at the back of throat, one at each side and play an integral role in immune system of the body.
Being part of the lymphatic system, tonsils produce white blood cells to fight out infections under normal condition. Once the tonsils become vulnerable in the face of invading pathogens, their ability to fight back infections is reduced and they become inflamed.
The viral infections which are commonly associated with causing tonsillitis include Epstein-Barr virus, influenza virus and the (common cold) rhinoviruses. Other tonsillitis related viruses include measles causing rubeola virus, hand, foot and mouth disease causing enterovirusues, diarrhea causing adenovirus and laryngitis and croup causing parainfluenza virus.
- Tonsillitis is commonly caused by virus but if left untreated, streptococcus bacteria can cause tonsillitis.
Interestingly, tonsillitis can also be a consequence of strep throat if it is left untreated. According to the American Academy of Family Physicians (AAFP), it is estimated that 15% to 30% cases of tonsillitis are due to bacterial invasion and most of them are caused by group A streptococcus bacteria. In the past, rheumatic fever and diphtheria was also associated with tonsillitis but now the relation is rarely found.
Tonsillitis can be recurrent or chronic in nature and it is characterized by the following symptoms:
- Painful swallowing
- Difficulty in swallowing food
- Bad breath
- Stiffness in neck
- Coarse voice
- Swollen lymph nodes leading to neck and jaw tenderness
- Yellow or white spots in tonsils
- Swelling and redness of tonsils
These symptoms are closely related to the symptoms of strep throat which makes diagnosis based solely on symptom observation difficult, leading to further testing.
Sore throat can be caused by many pathogens and is mostly a viral infection. Coxsackie virus is the most common cause of sore throat in summer and autumn and it lasts for about 10 days, mostly. Another viral infection, known as mononucleosis (mono), can also cause sore throat which can last for 4 weeks and the symptoms include:
- Swelling in gland in the neck
- Swelling in armpits and groin (region between abdomen and upper thigh)
- Chills and fever
Sometimes, it is caused by bacterial agents which is treated by antibiotics.
- Sore throat is not caused by Streptococcus pyogenes bacteria.
Treatment Of Strep Throat
As compared with infections that may arise from multiple groups of pathogens, treating strep throat is not challenging. All that is required is that after getting the strep throat infection confirmation from your doctor and the antibiotic prescription, you have to take your medications as indicated by the doctor.
If you do not adhere to the dosage and duration of antibiotic therapy, not only are you helping the infection to prolong but you are also giving room to antibiotic resistance to develop which can be a great health hazard later on.
Usually doctors prescribe antibiotics for 10 days to completely eradicate bacterial pathogen. At other times, a single shot of drug may be given as an alternate. However, the efficiency of drug through both modes remains similar.
- Amoxicillin or penicillin is the first line of antibiotic therapy. If one is allergic to penicillin then azithromycin, cephalexin or erythromycin are used.
- Take vit-B complex whenever antibiotics are taken.
The prescribed antibiotics for strep throat treatment include penicillin or amoxicillin for the people who are not allergic to penicillin. Known to be effective against a range of bacterial pathogens, penicillin remains the most favored antibiotic treatment for strep throat.
However, if you are allergic to penicillin, newer generation of antibiotics can be used which may include azithromycin, cephalexin or erythromycin.
In addition to these antibiotics, your doctor may also prescribe some over-the-counter medicines for fever and pain reduction.
In addition to taking medications on time, it is important for you to:
- Keep yourself hydrated by taking in plenty of fluids
- Have salt water gargles to soothe your sore throat
- Take plenty of rest
- Use humidifier in your room to keep your throat moist
- Use throat spray and lozenges for throat pain relief
- It is good to take vitamin C for 1 to 2 weeks, whenever weather is changing
Why Time Matters In Treating Strep Throat?
If strep throat is not treated well in time, the bacteria which reside in your system can developing complications. Although these complications are rare but they certainly are presently and cannot be ignored. These complications can arise as a result of the traces of strep infection left in the body or the body’s immune response to counteracting this infection.
Complications Of Strep Throat Infection
These infections can spread to other parts of the body like sinusitis or the middle ear. Furthermore, other complications of strep throat can lead to:
- Toxic shock syndrome
- Peritonsillar abscess i.e., collection of pus in the tissues which form tonsils leading to severe pain and difficulty in swallowing food. If the condition is recurrent in nature, surgical removal of tonsils through tonsillectomy is recommended.
- Lymph node infections
- Infection behind the pharynx known as retropharyngeal abscess
- Rheumatic fever, common in children between the age of 5 to 15 years. This is no common fever as it carries the potential of causing permanent damage to heart, however medications can help reduce the tissue inflammation.
- Glomerulonephritis i.e., inflammation of kidneys
- Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS).
Prevention Of Strep Throat
It is likely that you will spread strep throat infection to others if you work in a crowded place. Similarly, having close contact with family can put your family at risk of catching your infection. Thereby it is important for you to realize the responsibility that lies on your shoulder: “Do not make others ill”.
- Take days off from school or work and rest in your bed.
- Reduce your close interactions to loved ones. Don’t cuddle or kiss them until you recover or at least 24 hours after you started taking antibiotics.
- Cover your mouth with a handkerchief or a tissue while coughing or sneezing.
- Properly trash the used tissue papers.
- If you are out of tissues, don’t cough over your hand. Doing so can easily transfer infection droplets from your hands to others through touching or shaking hands. If you touch a surface with contaminated hands, people can also get infected by touching that surface.
- Wash your hands often and if you are at a place where you can’t wash your hands, use an alcohol-based hand sanitizer.
- The utensils, glasses and cutlery used by infected person should be thoroughly washed.
Prevention Of Food borne Spread Of Strep Throat
According to the Infectious Disease Society of America (IDSA), the spread of foodborne infections can be minimized by some simple precautions. These precautionary measures include:
- Avoid preparing food for others when you are ill. Particularly if the symptoms of your illness include sneezing, coughing, diarrhea, respiratory infection or vomiting.
- In case you are getting treated for your illness, ask your doctor when you should resume with your cooking routine. Once your illness becomes non-contagious, you can cook without fearing the spread of disease.
- If you are preparing food in large qualities or batches, be assured that the food is stored either cold or hot. Experts have marked temperatures between 410F and 1400F as “temperature danger zone” as it is the optimal breeding temperature range for disease causing bacteria.
- It is recommended that you use a thermometer to check the temperature of the food you have prepared or you are storing to be sure that the food items meet proper (safe from bacterial contamination) temperature requirements.
- Furthermore, if you are worrying about preparing food for large groups and the associated risk of contamination, it is advised to read the educational material made available by the United States Department of Agriculture (USDA).
Vitamin C And Strep Throat
While studies remain divided on linking vitamin C with strep throat, evidence cannot be ignored that suggests that taking adequate amount of vitamin C during strep throat can help get rid of symptoms quickly.
As vitamin C helps in strengthening immune system by stimulating the function of white blood cells, particularly lymphocytes, neutrophils and phagocytes, it helps in fighting out diseases. In this context, neutrophils help fight against bacterial and virus pathogens, leading to its efficacy against strep throat as well.
Experts suggest taking vitamin C for cold, flu or sore throat can also help individuals reduce their risk of developing serious respiratory conditions.
According to the National Institute of Health, normally an adult male should consume 90 milligram/day of vitamin C and adult women should consume 75 milligrams/day of vitamin C. For pregnant women, the daily intake should be 85 milligram/day and for women who breastfeed their children, it is 120 milligram/day.
Home Remedies And Strep Throat
Home remedies can help you when taken in addition to your antibiotic drugs. These home remedies include:
- Herbal teas and clear soups can be of great help for soothing throat pain.
- Use of honey, ginger and lemon in herbal tea preparation can be helpful.
- Drinking chamomile tea is good for pain relief.
- Addition of cinnamon, onion, cloves, black pepper and garlic to your soups can do wonders.
- Using diluted form of apple cider vinegar for gargles can help kill the bacteria in your throat.
- Warm beverages can provide relief.
Eat frozen desserts like popsicles and ice creams.
Co Author : Fizza Akbar