Pertussis Research Paper
Pertussis, also known as whooping cough, is a highly contagious respiratory tract infection of humans that is caused by a gram-negative bacterial pathogen Bordetella pertussis. These bacteria bind to ciliated cells that line the respiratory tract by obstructing their ciliary movement and killing the cells. B. pertussis can be transmitted from one person to another through respiratory droplets such as coughing, sneezing, or sharing a breathing space. B.pertussis host range can be found only in humans (sole reservoir) most especially, the adults and adolescents with an undiagnosed infection who may transmit the infection to infants and children through droplets transmission (http://wwwpublichealth.gc.ca). Pertussis is a re-emerging disease, that is, the incidence has recently been on the rise due to parents refusal to vaccinate their infants because of their belief that vaccines may not be safe, and also due to the waning immunity among vaccinated adults (Krause et al.,1992).
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B.
pertussis was first isolated in pure culture in 1906 by Bordet and Gengou after observing the organism microscopically in the sputum of an infected patient (Mattoo and Cherry 2005). Pertussis is a severe disease in children below 10 years of age, this caused several infantile spasms and sudden infant death syndrome which first led in the mid 1940s to the introduction of a mono-component whole-cell pertussis vaccines, but which in 1947 was replaced by a vaccine combination with diphtheria and tetanus toxoids added (DTP). The availability of DTP vaccine helped to decrease the rate of pertussis cases as at that time (Tortora et al.,2007). However, newer and safer acellular vaccines-diphtheria, tetanus, and pertussis (DTaP), and tetanus, diphtheria, and pertussis (Tdap) are known for their specific roles in prevention of pertussis from spreading from one person to another
(http://www.cdc.gov).
However, DTap are designated for children below 7 years (6 weeks to 6 years) of age which helps to develop their immunity towards pertussis, while Tdap vaccines are designated for adolescents and adults in order to help “boost their immunity as the effectiveness of childhood vaccination decreases” (Tortora, 2007). Both vaccines provide protection from pertussis and prevent its transmission from one person to another. There are three stages of pertussis in adolescents and adults; the initial stage catarrhal stage, paroxysmal stage, and convalescence stage. The disease affects mainly infants and young children, as well as people of all ages. It can be prevented by immunization with the pertussis vaccine. It occurs mostly at night.
Etiology
Bordetella pertussis is a small (approximately 0.8 μm by 0.4 μm), rod-shaped, coccoid, or ovoid Gram-negative bacterium that is encapsulated and non-sporulating. It is a strict aerobe. It is arranged singly or in small groups and is not easily distinguished from Haemophilus species. B pertussis and B parapertussis are non-motile. Numerous antigens and biologically active structural components have been demonstrated in B pertussis, although their exact chemical structure and location in the bacterial cell are known only in part.
Epidemiology
Pertussis exists and widely spread through out the world. It is a highly communicable disease that has killed and infected about 80 - 90% of children (http://www.cdc.gov). “Pertussis is a human disease with no trace of known animal or environmental reservoir” (Seema and Cherry, 2005). Pertussis is a disease that is associated with human beings and can survive outside the body for few days. It is a disease that occurs being transmitted by respiratory route through contact with respiratory droplets such as coughing and sneezing, contaminated objects, and direct contact with an infected person.This disease can be transmitted to infants through their family members or caregivers. Pertussis infection are highly contagious during catarrhal and paroxysmal stages. After an initial incubation period of between one to two weeks, pertussis severity increases and begins with the initial stage called the catarrhal stage in which affected people experience signs and symptoms of common cold like sneezing, low-grade fever and progressive coughing (CDC, 2015). The prolonged period of coughing later transition to paroxysmal stage, which is characterized by intense and spasmodic coughing that usually lasts two to four weeks. This is the stage “whoop” sound can be heard caused by gasping person inhaling between coughs. When ciliary action is compromised, mucus accumulates, and the infected person desperately attempts to cough up these mucus accumulations. The violence of the coughing in small children can actually result in broken ribs. Gasping for air between coughs causes a whooping sound, hence the informal name of the disease. Coughing episodes occur several times a day for 1 to 6 weeks. The convalescence stage, the third stage, may last for months. It is characterized by chronic cough because infants are less capable of coping with the effort of coughing to maintain an airway, irreversible damage to the brain occasionally occurs (Tortora et al., 2013).
Pathogenesis
Pertussis is primarily a toxin-mediated disease. The bacteria attach to the cilia of the respiratory epithelial cells, produce toxins that paralyze the cilia, and cause inflammation of the respiratory tract, which interferes with the clearing of pulmonary secretions. Pertussis antigens appear to allow the organism to evade host defenses, in that lymphocytosis is promoted but chemotaxis is impaired. Until recently it was thought that B. pertussis did not invade the tissues. However, recent studies have shown the bacteria to be present in alveolar macrophages (CDC, 2015).
Virulence Factors
While many microbiologists and researchers do not fully understand how B. pertussis becomes pathogenic, there are several virulence factors associated with initial infection. These bacteria produce a number of virulence factors such as pertussis toxin, tracheal cytotoxin, filamentous haemagglutinin, fimbriae and pertactin, which binds to ciliated cells in the trachea that line the upper respiratory tract and hinders the movement of cilia and damages ciliated epithelial cells thereby causing the airways to swell (Tortora et al., 2007, Smith, Guzman and Walker, 2001)
Upon entrance into the respiratory tract, B. pertussis colonizes in the host via filamentous hemagglutinin (FHA) and the pertussis toxin. FHA, a large protein that forms filamentous structures on the cell surface, binds to galactose residues on the surface of the trachea’s ciliated epithelial cells. The pertussis toxin, a protein composed of six subunits: S1, S2, S3, (2)S4, and S5, is also involved in adherence to the tracheal epithelium. Some of these components function as adhesins, binding the bacteria to the host cell, while others utilize different receptors, such as binding to a glycolipid found specifically on tracheal epithelium, or binding to a glycoprotein found primarily on phagocytic cells. Contributing to its virulence, B. pertussis also produces its own toxins, such as invasive adenylate cyclase, a single polypeptide that enters epithelial cells, locally reduces phagocytic activity, and lyses red blood cells, thus initiating infection. Lethal toxin, formerly called dermonecrotic toxin, is a protein that causes inflammation where B. pertussis has colonized. Tracheal toxin, a peptidoglycan fragment, destroys ciliated cells, stimulates the release of interleukin-1, and causes fever (Babu et al, 2007).
Diagnosis
Diagnosis of pertussis is primarily based on symptoms and clinical signs. However, when the symptoms are not obvious, pertussis may be difficult to diagnose. In order to diagnose a patient for pertussis, several tests are commonly used such as culture, PCR, and serology. But the gold standard that has the excellent specificity is known as culture, which is normally use to detect pertussis diagnosis during an outbreak. During the laboratory test, the pathogen can be cultured from a nasopharyngeal swabs or nasopharyngeal secretions in which throat swap is being inserted through the nose on a thin wire and held in the throat while the patient coughs. Culture of the fastidious pathogen requires care. As alternatives to culture, Polymerase chain reaction (PCR) methods can also be used to test the swabs for presence of the pathogen, a procedure that is required to diagnose the disease in infants (Tortora et al., 2013). The test duration takes a long time, and pertussis usually grows in the laboratory after 3 to 4 days of incubation at 37° C (Finger and Koenig, 1996).
Treatment
Early treatment of pertussis is very important because it will help in preventing the transmission of the diseases from one person to another. Treatment conducted after three weeks of the illness commencement can make the bacteria to cause a severe damage to the body because the diagnosis came too late. However, there are several recommended antibiotics / antimicrobial agents that can help in the treatment or chemoprophylaxis of pertussis such as macrolide antibiotics (azithromycin and clarithromycin), erythromycin, and trimethoprim-sulfamethoxazole (http://www.cdc.gov). Erythromycin is administered to an infected person during catarrhal stage. During this stage, erythromycin reduced the period of symptoms and eliminate the microorganism from the upper respiratory tract within few days because early treatment of pertussis is essential when the antibiotic is still effective (Mattoo and Cherry, 2005).
However, early treatment of pertussis will also help to prevent and diminish the patient’s ability to transmit the disease to uninfected people. If an infant or a child acquire pertussis, its treatment can commence at home or in a hospital. If the child has to be treated at home, the child’s home must be free from irritants that may lead to cough, smoke, and dust particles. Encourage the child to take a lot of fluids to prevent dehydration, and always sanitize and wash hands properly. If the infant has to be treated in hospital,they require constant supervision by ensuring that their breathing passages is clear and can be able to draw out mucus. This is because they might have difficulty breathing while coughing. Oxygen may be given in order to boost their breathing. Supervised intravenous fluid might be given if the coughing becomes severe thereby causing the child to have difficulty eating and taking fluids. Also, standard safety precautions should be practiced by washing hands always and sanitizing the whole surrounding (http://www.cdc.gov).
Prevention
Pertussis can be prevented from babies, children, teens, and adults through vaccination. This can be achieved by getting them vaccinated with a DTap vaccination (diphtheria, tetanus, and pertussis). This vaccine provides protection for children against pertussis infection. Five DTap vaccines are highly recommended to be given to infants, babies, and children. Another vaccine given to teens and adults is called Tdap vaccine, this is a vaccine that boost immune system and protects them against diphtheria, tetanus, and pertussis. Another way to prevent spread of pertussis during outbreak is by ensuring that susceptible children are separated from infected children, and are not allowed to attend social activities and school together with infected children during the first four weeks.
Other standard precautions and infection control needed to break the chain of pertussis infection are listed below:
Always wash hands with soap and warm water for 20 seconds after touching a contaminated object, coughing or sneezing, using the bathroom, and touching the garbage.
Sneeze in your upper sleeve if you do not have a tissue or cover your mouth and nose with tissue when you cough and sneeze.
Use a hand sanitizer if soap and water are not available.
Pregnant women should be vaccinated with Tdap vaccine during their third trimester even if they have been immunized before in order to develop antibodies that can pass protection to the baby before birth.
Always get enough sleep, exercise regularly, and eat healthy food in order to help boost your immune system in fighting against pertussis infection.
B.pertussis, a highly contagious disease of the respiratory system has been a severe disease in infants and children below ten years.The symptoms of this disease has been life threatening to infants and children which led to the introduction of the new acellular vaccines DTap and Tdap in 1940s. Both vaccines help to eliminate and prevent pertussis from transmitting from one person to another. But recently, reported cases of pertussis have been on increase since early 1980s and got to its high peak in 2004 as a result of waning immunity. It seems that the acellular vaccines being used today does not provide adequate protection against pertussis than the whole cell vaccines coupled with some parents refusal to vaccinate their babies which made them eighty percent more susceptible to contracting the infection than children who received all the five doses of DTap. These contributed to the re-emergence of pertussis thereby causing an outbreak. If parents continue to vaccinate their children and follow all the necessary standard precautions and infection control needed to break the chain of pertussis transmission, I believe that pertussis could be highly contained
B.
pertussis was first isolated in pure culture in 1906 by Bordet and Gengou after observing the organism microscopically in the sputum of an infected patient (Mattoo and Cherry 2005). Pertussis is a severe disease in children below 10 years of age, this caused several infantile spasms and sudden infant death syndrome which first led in the mid 1940s to the introduction of a mono-component whole-cell pertussis vaccines, but which in 1947 was replaced by a vaccine combination with diphtheria and tetanus toxoids added (DTP). The availability of DTP vaccine helped to decrease the rate of pertussis cases as at that time (Tortora et al.,2007). However, newer and safer acellular vaccines-diphtheria, tetanus, and pertussis (DTaP), and tetanus, diphtheria, and pertussis (Tdap) are known for their specific roles in prevention of pertussis from spreading from one person to another
(http://www.cdc.gov).
However, DTap are designated for children below 7 years (6 weeks to 6 years) of age which helps to develop their immunity towards pertussis, while Tdap vaccines are designated for adolescents and adults in order to help “boost their immunity as the effectiveness of childhood vaccination decreases” (Tortora, 2007). Both vaccines provide protection from pertussis and prevent its transmission from one person to another. There are three stages of pertussis in adolescents and adults; the initial stage catarrhal stage, paroxysmal stage, and convalescence stage. The disease affects mainly infants and young children, as well as people of all ages. It can be prevented by immunization with the pertussis vaccine. It occurs mostly at night.
Etiology
Bordetella pertussis is a small (approximately 0.8 μm by 0.4 μm), rod-shaped, coccoid, or ovoid Gram-negative bacterium that is encapsulated and non-sporulating. It is a strict aerobe. It is arranged singly or in small groups and is not easily distinguished from Haemophilus species. B pertussis and B parapertussis are non-motile. Numerous antigens and biologically active structural components have been demonstrated in B pertussis, although their exact chemical structure and location in the bacterial cell are known only in part.
Epidemiology
Pertussis exists and widely spread through out the world. It is a highly communicable disease that has killed and infected about 80 - 90% of children (http://www.cdc.gov). “Pertussis is a human disease with no trace of known animal or environmental reservoir” (Seema and Cherry, 2005). Pertussis is a disease that is associated with human beings and can survive outside the body for few days. It is a disease that occurs being transmitted by respiratory route through contact with respiratory droplets such as coughing and sneezing, contaminated objects, and direct contact with an infected person.This disease can be transmitted to infants through their family members or caregivers. Pertussis infection are highly contagious during catarrhal and paroxysmal stages. After an initial incubation period of between one to two weeks, pertussis severity increases and begins with the initial stage called the catarrhal stage in which affected people experience signs and symptoms of common cold like sneezing, low-grade fever and progressive coughing (CDC, 2015). The prolonged period of coughing later transition to paroxysmal stage, which is characterized by intense and spasmodic coughing that usually lasts two to four weeks. This is the stage “whoop” sound can be heard caused by gasping person inhaling between coughs. When ciliary action is compromised, mucus accumulates, and the infected person desperately attempts to cough up these mucus accumulations. The violence of the coughing in small children can actually result in broken ribs. Gasping for air between coughs causes a whooping sound, hence the informal name of the disease. Coughing episodes occur several times a day for 1 to 6 weeks. The convalescence stage, the third stage, may last for months. It is characterized by chronic cough because infants are less capable of coping with the effort of coughing to maintain an airway, irreversible damage to the brain occasionally occurs (Tortora et al., 2013).
Pathogenesis
Pertussis is primarily a toxin-mediated disease. The bacteria attach to the cilia of the respiratory epithelial cells, produce toxins that paralyze the cilia, and cause inflammation of the respiratory tract, which interferes with the clearing of pulmonary secretions. Pertussis antigens appear to allow the organism to evade host defenses, in that lymphocytosis is promoted but chemotaxis is impaired. Until recently it was thought that B. pertussis did not invade the tissues. However, recent studies have shown the bacteria to be present in alveolar macrophages (CDC, 2015).
Virulence Factors
While many microbiologists and researchers do not fully understand how B. pertussis becomes pathogenic, there are several virulence factors associated with initial infection. These bacteria produce a number of virulence factors such as pertussis toxin, tracheal cytotoxin, filamentous haemagglutinin, fimbriae and pertactin, which binds to ciliated cells in the trachea that line the upper respiratory tract and hinders the movement of cilia and damages ciliated epithelial cells thereby causing the airways to swell (Tortora et al., 2007, Smith, Guzman and Walker, 2001)
Upon entrance into the respiratory tract, B. pertussis colonizes in the host via filamentous hemagglutinin (FHA) and the pertussis toxin. FHA, a large protein that forms filamentous structures on the cell surface, binds to galactose residues on the surface of the trachea’s ciliated epithelial cells. The pertussis toxin, a protein composed of six subunits: S1, S2, S3, (2)S4, and S5, is also involved in adherence to the tracheal epithelium. Some of these components function as adhesins, binding the bacteria to the host cell, while others utilize different receptors, such as binding to a glycolipid found specifically on tracheal epithelium, or binding to a glycoprotein found primarily on phagocytic cells. Contributing to its virulence, B. pertussis also produces its own toxins, such as invasive adenylate cyclase, a single polypeptide that enters epithelial cells, locally reduces phagocytic activity, and lyses red blood cells, thus initiating infection. Lethal toxin, formerly called dermonecrotic toxin, is a protein that causes inflammation where B. pertussis has colonized. Tracheal toxin, a peptidoglycan fragment, destroys ciliated cells, stimulates the release of interleukin-1, and causes fever (Babu et al, 2007).
Diagnosis
Diagnosis of pertussis is primarily based on symptoms and clinical signs. However, when the symptoms are not obvious, pertussis may be difficult to diagnose. In order to diagnose a patient for pertussis, several tests are commonly used such as culture, PCR, and serology. But the gold standard that has the excellent specificity is known as culture, which is normally use to detect pertussis diagnosis during an outbreak. During the laboratory test, the pathogen can be cultured from a nasopharyngeal swabs or nasopharyngeal secretions in which throat swap is being inserted through the nose on a thin wire and held in the throat while the patient coughs. Culture of the fastidious pathogen requires care. As alternatives to culture, Polymerase chain reaction (PCR) methods can also be used to test the swabs for presence of the pathogen, a procedure that is required to diagnose the disease in infants (Tortora et al., 2013). The test duration takes a long time, and pertussis usually grows in the laboratory after 3 to 4 days of incubation at 37° C (Finger and Koenig, 1996).
Treatment
Early treatment of pertussis is very important because it will help in preventing the transmission of the diseases from one person to another. Treatment conducted after three weeks of the illness commencement can make the bacteria to cause a severe damage to the body because the diagnosis came too late. However, there are several recommended antibiotics / antimicrobial agents that can help in the treatment or chemoprophylaxis of pertussis such as macrolide antibiotics (azithromycin and clarithromycin), erythromycin, and trimethoprim-sulfamethoxazole (http://www.cdc.gov). Erythromycin is administered to an infected person during catarrhal stage. During this stage, erythromycin reduced the period of symptoms and eliminate the microorganism from the upper respiratory tract within few days because early treatment of pertussis is essential when the antibiotic is still effective (Mattoo and Cherry, 2005).
However, early treatment of pertussis will also help to prevent and diminish the patient’s ability to transmit the disease to uninfected people. If an infant or a child acquire pertussis, its treatment can commence at home or in a hospital. If the child has to be treated at home, the child’s home must be free from irritants that may lead to cough, smoke, and dust particles. Encourage the child to take a lot of fluids to prevent dehydration, and always sanitize and wash hands properly. If the infant has to be treated in hospital,they require constant supervision by ensuring that their breathing passages is clear and can be able to draw out mucus. This is because they might have difficulty breathing while coughing. Oxygen may be given in order to boost their breathing. Supervised intravenous fluid might be given if the coughing becomes severe thereby causing the child to have difficulty eating and taking fluids. Also, standard safety precautions should be practiced by washing hands always and sanitizing the whole surrounding (http://www.cdc.gov).
Prevention
Pertussis can be prevented from babies, children, teens, and adults through vaccination. This can be achieved by getting them vaccinated with a DTap vaccination (diphtheria, tetanus, and pertussis). This vaccine provides protection for children against pertussis infection. Five DTap vaccines are highly recommended to be given to infants, babies, and children. Another vaccine given to teens and adults is called Tdap vaccine, this is a vaccine that boost immune system and protects them against diphtheria, tetanus, and pertussis. Another way to prevent spread of pertussis during outbreak is by ensuring that susceptible children are separated from infected children, and are not allowed to attend social activities and school together with infected children during the first four weeks.
Other standard precautions and infection control needed to break the chain of pertussis infection are listed below:
Always wash hands with soap and warm water for 20 seconds after touching a contaminated object, coughing or sneezing, using the bathroom, and touching the garbage.
Sneeze in your upper sleeve if you do not have a tissue or cover your mouth and nose with tissue when you cough and sneeze.
Use a hand sanitizer if soap and water are not available.
Pregnant women should be vaccinated with Tdap vaccine during their third trimester even if they have been immunized before in order to develop antibodies that can pass protection to the baby before birth.
Always get enough sleep, exercise regularly, and eat healthy food in order to help boost your immune system in fighting against pertussis infection.
B.pertussis, a highly contagious disease of the respiratory system has been a severe disease in infants and children below ten years.The symptoms of this disease has been life threatening to infants and children which led to the introduction of the new acellular vaccines DTap and Tdap in 1940s. Both vaccines help to eliminate and prevent pertussis from transmitting from one person to another. But recently, reported cases of pertussis have been on increase since early 1980s and got to its high peak in 2004 as a result of waning immunity. It seems that the acellular vaccines being used today does not provide adequate protection against pertussis than the whole cell vaccines coupled with some parents refusal to vaccinate their babies which made them eighty percent more susceptible to contracting the infection than children who received all the five doses of DTap. These contributed to the re-emergence of pertussis thereby causing an outbreak. If parents continue to vaccinate their children and follow all the necessary standard precautions and infection control needed to break the chain of pertussis transmission, I believe that pertussis could be highly contained