Bordetella pertussis: Infectious substances pathogen safety data sheet

For more information on Bordetella pertussis, see the following:

• Diseases and conditions: Pertussis (whooping cough)

Section I – Infectious agent

Name

Bordetella pertussis

Agent type

Bacteria

Taxonomy

Family

Alcaliggenaceae

Genus

Bordetella

Species

pertussis

Synonym or cross-reference

Bordetella pertussis causes pertussis, which is also known as whooping cough^{Footnote 1Footnote 2}.

Characteristics

Brief description

B. pertussis is a small (0.8 µm by 0.4 µm), encapsulated, non-sporulating, Gram-negative, non-motile bacteria^{Footnote 3Footnote 4}. Cells can be rod-shaped, coccoid, or ovoid and are arranged singly or in small groups. The genome of B. pertussis is 4.1 Mbp, with a G+C content of 67.72% and 3,816 coding sequences^{Footnote 5}.

Properties

B. pertussis is a strictly aerobic bacterium that produces various virulence factors and toxins that contribute to its pathogenicity, including pertussis toxin (PT), adenylate cyclase toxin (AC), dermonecrotic toxin (DNT), and tracheal cytotoxin (TCT)^{Footnote 1Footnote 3}. The BvgAS two-component signal transduction system controls expression of various virulence factors, including PT, AC, and DNT, and is critical to the bacterium's pathogenicity^{Footnote 1}. PT, which is unique to B. pertussis, is thought to induce lymphocytosis and insulin secretion, and alter T cell responsiveness. AC plays a role in immune evasion through inhibiting the migration and activation of phagocytes, suppressing cytotoxicity of innate immune cells, and blocking bactericidal nitric oxide in macrophages. DNT has been shown to induce cell necrosis in vitro and vasoconstriction in primates. TCT induces the production of pro-inflammatory cytokines and nitric oxide synthase for nitric oxide production and is thought to cause the characteristic cough paroxysms.

Section II – Hazard identification

Pathogenicity and toxicity

Pertussis most commonly presents as whooping cough; however, there are many signs and symptoms of the disease that vary depending on the age of the infected individual^{Footnote 1}. Infection may range from asymptomatic presentation to mild upper respiratory disease and severe and persistent coughing for weeks to months. This is especially common in infants and young children. Illness lasts 6 to 12 or more weeks and there are three stages of disease associated with infection in infants and children: catarrhal, paroxysmal/spasmodic, and convalescent^{Footnote 1Footnote 6Footnote 7}. The catarrhal stage is characterized by low-grade fever (<20% of cases), malaise, sore throat, congestion, mild dry cough, and rhinorrhea. This phase generally lasts for 2 weeks, and pertussis is not often suspected at this stage due to similarities in the clinical presentation with circulating viruses. The paroxysmal/spasmodic stage is associated with violent coughing (paroxysms) that can occur for several minutes and happen more than 30 times a day, mostly at night. Paroxysms are caused by toxins or mucous hardening in the respiratory tract, which is difficult to dislodge. Other symptoms during this period include cyanosis, eye proptosis, tongue protrusion, thick mucous, engorgement of neck veins, vomiting, and fatigue. This stage lasts for 2-3 weeks, with paroxysms increasing in frequency with time, but gradually decline after the third week. During the convalescent stage, paroxysms become less frequent, and are replaced by a milder, chronic, non-paroxysmal cough which can last up to 6 weeks. Relapse may occur if another respiratory infection is acquired at this stage. This phase lasts from 2 weeks to a few months.

The clinical presentation in adolescents and adults is similar to that of infants and children, but may be milder, resulting in undetected cases. The classic paroxysms may be absent in this age group, thus presentation with a cough for longer than three weeks should be potentially indicative of pertussis. The cough may last from three to eight weeks and adults may experience sweating episodes in between bouts of coughing. Atypical presentation in adults includes prolonged cough, paroxysms, whoop, phlegm, vomiting, and intracranial hemorrhage^{Footnote 6}.

Delayed diagnosis of pertussis is more likely to result in clinical complications and sequelae^{Footnote 1}. Young infants belong to the highest risk group for severe outcomes, including respiratory failure and death. Infants hospitalized for pertussis have presented with apnea, pneumonia, and convulsions. Further, infants and young children may become coinfected with other pathogens, such as respiratory syncytial virus (RSV), parainfluenza virus, Mycoplasma pneumoniae, adenovirus, and influenza A and B viruses. Complications in adults most often include insomnia, apnea, weight loss, urinary incontinence, syncope, and rib fracture. Less common manifestations include pneumonia, otitis media, and, rarely, death. Mortality rates in infants are reported to be 1-1.6%, while in adolescents and adults, it is reported to be ~0.01%^{Footnote 1}.

Epidemiology

Pertussis is considered an endemic disease in many countries and sporadic outbreaks occur around the world^{Footnote 1}. Prior to vaccination efforts, 95% of people experienced a pertussis infection^{Footnote 8}. Epidemics would occur every 3-4 years due to cycling population immunity^{Footnote 1}. Whole-cell pertussis vaccines started being implemented in the 1940s, later replaced by acellular pertussis vaccines, resulting in a significant decrease in reported cases by the 1970s^{Footnote 1Footnote 9}. Between 1990 and 2019, the global annual incidence number of pertussis was reduced to 19,519,182 from 33,072,794, which represents a decrease of approximately 41%. Despite a reduced incidence, the 3-year epidemic cycle persists in many countries, and pertussis remains one of the main causes of vaccine-preventable death^{Footnote 6}. In 2019, western sub-Saharan Africa experienced the highest number of morbidities, disability-adjusted life years, and fatalities^{Footnote 10}. In Canada, from 2005 to 2019, 33,481 cases of pertussis were diagnosed, with infants accounting for 13.1% of cases^{Footnote 11}. During this period, there were 1593 acute care pertussis hospitalizations and 17 deaths, all of which occurred in infants less than one year of age. Risk factors that significantly increased likelihood of fatality in infant pertussis cases include lower birth weight, younger gestational age, younger age at time of cough onset, higher white blood cell and lymphocyte counts, and maternal pertussis vaccination^{Footnote 12Footnote 13}. Adolescents or adults with underlying conditions, such as asthma, chronic obstructive pulmonary disorder, obesity, immunodeficiency, and/or past smokers, have an increased risk of exacerbated symptoms and hospitalization^{Footnote 14}. Length of hospital stays also increases with age.

Host range

Natural host

Humans are the only natural host of B. pertussis^{Footnote 1Footnote 9}.

Other hosts

Suckling pigs, primates, and rodents have been experimentally infected^{Footnote 9}.

Infectious dose

A study published in 1933 found that 140 B. pertussis organisms were capable of infecting two unvaccinated children^{Footnote 15}.

Incubation period

The incubation period of pertussis or whooping cough is typically 7-10 days^{Footnote 1}. However, periods of up to 4 weeks have been reported.

Communicability

B. pertussis is primarily transmitted from person-to-person through aerosolized respiratory droplets spread by cough or sneeze, requiring close contact or repeated and prolonged exposure^{Footnote 1Footnote 7Footnote 14}. Respiratory secretions are most infectious during the catarrhal stage, but efficient transmission generally occurs during the first three weeks after onset of cough^{Footnote 7}. The estimated basic reproductive number (R_o) of B. pertussis, which is the expected number of secondary cases arising from a primary case in a completely susceptible population, is 12-17^{Footnote 1}. In areas with high vaccination rates, the R_o remains between 5-6 suggesting that B. pertussis continues to circulate even in areas of high vaccination^{Footnote 16}.

Section III – Dissemination

Reservoir

Adults and adolescents serve as reservoirs of B. pertussis and are major sources of transmission to partially immunized infants and children^{Footnote 17}. There is a high prevalence of asymptomatic infection among household-exposed individuals^{Footnote 2}.

Zoonosis

None.

Vectors

None.

Section IV – Stability and viability

Drug susceptibility/resistance

Azithromycin, erythromycin, clarithromycin, and trimethoprim-sulfamethoxazole (TMP-SMZ) are effective for the treatment of pertussis^{Footnote 7}. A study in China revealed that strains with an A2047G mutation of the 23S rRNA gene were resistant to erythromycin^{Footnote 18}.

Susceptibility to disinfectants

An ethanol-based compound was associated with a 5.47 log reduction in B. pertussis bacterial count after exposure for 30 seconds^{Footnote 19}. Treatment with a propanol-based compound for 30 seconds resulted in a 5.42 log reduction. A quaternary ammonium compound (QAC) product was also tested and was found to reduce the bacterial count by 5.57 log after 30 seconds.

Physical inactivation

B. pertussis can succumb to drying, ultraviolet light, and temperatures above 120°F to 130°F^{Footnote 20}.

Survival outside host

B. pertussis lacks an environmental reservoir and is likely incapable of long-term survival outside the host due to loss of genes that allow for the use of alternative nutrient sources^{Footnote 5Footnote 17}.

Section V – First aid/medical

Surveillance

Differential diagnosis is important in distinguishing pertussis from other illnesses with similar clinical presentations^{Footnote 7Footnote 21Footnote 22}. There are various methods available to confirm the diagnosis, including bacterial culture, polymerase chain reaction (PCR), single-serum enzyme linked immunosorbent assay (ELISA). In practice, if the cough persists for less than 2 weeks in adolescents and adults or 3 weeks in children, a nasopharyngeal specimen should be obtained for PCR or culture. In adults, if the cough lasts longer than 2 weeks, single-serum ELISA to detect IgG or IgA antibodies should be used as long as they haven't received the vaccine in the previous 12 months. This approach can also be used in children if they haven't been immunized within a year. Serological diagnosis should not be used for infants less than 6 months of age due to the presence of maternal antibodies.

Note: The specific recommendations for surveillance in the laboratory should come from the medical surveillance program, which is based on a local risk assessment of the pathogens and activities being undertaken, as well as an overarching risk assessment of the biosafety program as a whole. More information on medical surveillance is available in the Canadian Biosafety Handbook.

First aid/treatment

Antibiotics are the primary treatment^{Footnote 7Footnote 21}. Oral erythromycin for 14 days, in both children and adults, has been shown to improve symptoms and reduce contagiousness if administered early in the course of illness. Azithromycin, clarithromycin, and trimethoprim-sulfamethoxazole (TMP-SMZ) can also be used to treat pertussis. Beyond antibiotics, supportive care is also used to manage pertussis, particularly in hospitalized patients^{Footnote 7}. This involves maintaining hydration and nutrition while avoiding factors that promote bouts of coughing. In cases of pneumonia or respiratory distress, gentle suction to remove secretions and well-humidified oxygen may be used. Assisted ventilation may be necessary in severe infections.

Note: The specific recommendations for first aid/treatment in the laboratory should come from the post-exposure response plan, which is developed as part of the medical surveillance program. More information on the post-exposure response plan can be found in the Canadian Biosafety Handbook.

Immunization

There are eight acellular pertussis-containing vaccines available for use in Canada, including Adacel (Tdap), Adacel-Polio (Tdap-IPV), Boostrix (Tdap), Boostrix-Polio (Tdap-IPV), Infanrix-IPV/Hib (DTaP-IPV-Hib), Infanrix hexa (DTaP-HB-IPV-Hib), Pediacel (DTaP-IPV-Hib), and Quadracel (DTaP-IPV)^{Footnote 23}. All individuals can be vaccinated, although the choice of vaccine and schedule of administration may vary. Vaccination with Tdap is safe for pregnant individuals and is recommended regardless of immunization history^{Footnote 1Footnote 23}. Vaccination should occur between 27 and 32 weeks of gestation, but the period between 13 and 26 weeks of gestation can also be considered.

Note: More information on the medical surveillance program can be found in the Canadian Biosafety Handbook, and by consulting the Canadian Immunization Guide.

Prophylaxis

Routine vaccination involving acellular pertussis vaccines is recommended for pre-exposure prophylaxis as there is an 85% efficacy following one dose and 90% after receiving a booster dose^{Footnote 23}. Antibiotic treatment is used as post-exposure prophylaxis and has been shown to improve symptoms and reduce contagiousness if delivered early in illness^{Footnote 7Footnote 21}. The non-macrolide antibiotic, TMP-SMZ, is contraindicated in pregnant women, nursing mothers, or infants less than two months old due to risk of neurological damage in infants^{Footnote 1}.

Note: More information on prophylaxis as part of the medical surveillance program can be found in the Canadian Biosafety Handbook.

Section VI – Laboratory hazard

Laboratory-acquired infections

In 1983, two cases of laboratory-acquired infections were confirmed as B. pertussis was detected in both individuals; however, the mode of exposure was not described^{Footnote 24}. Another exposure occurred prior to 1995 where a laboratory worker in Georgia became infected with an epidemic strain of B. pertussis^{Footnote 25}. Infection was confirmed after isolating the bacteria from the individual. He presented with a cough that persisted for six weeks.

Note: Please consult the Canadian Biosafety Standard and Canadian Biosafety Handbook for additional details on requirements for reporting exposure incidents.

Sources/specimens

B. pertussis has been detected in nasopharyngeal secretions^{Footnote 7}.

Primary hazards

Inhalation of airborne or aerosolized infectious material is the primary hazard associated with exposure to B. pertussis^{Footnote 1Footnote 7Footnote 14}.

Special hazards

None.

Section VII – Exposure controls/personal protection

Risk group classification

Bordetella pertussis is a Risk Group 2 Human Pathogen and a Risk Group 1 Animal Pathogen^{Footnote 26Footnote 27}.

Containment requirements

Containment Level 2 facilities, equipment, and operational practices outlined in the Canadian Biosafety Standard for work involving infectious or potentially infectious materials, animals, or cultures.

Protective clothing

The applicable Containment Level 2 requirements for personal protective equipment and clothing outlined in the Canadian Biosafety Standard are to be followed. The personal protective equipment could include the use of a labcoat and dedicated footwear (e.g., boots, shoes) or additional protective footwear (e.g., boot or shoe covers) where floors may be contaminated (e.g., animal cubicles, post mortem rooms), gloves when direct skin contact with infected materials or animals is unavoidable, and eye protection where there is a known or potential risk of exposure to splashes.

Note: A local risk assessment will identify the appropriate hand, foot, head, body, eye/face, and respiratory protection, and the personal protective equipment requirements for the containment zone and work activities must be documented.

Other precautions

The main mode of transmission of B. pertussis, exposure of mucous membrane to infectious aerosols, justifies the use of a BSC or other primary containment devices for activities with open vessel; centrifugation to be carried out in sealed safety cups or rotors that are unloaded using a mechanism that prevents their release. Respiratory protection to be considered when a BSC or other primary containment device cannot be used; inward airflow is required for work involving large animals or large scale activities.

Use of needles and syringes are to be strictly limited. Bending, shearing, re-capping, or removing needles from syringes are to be avoided, and if necessary, performed only as specified in standard operating procedures (SOPs). Additional precautions are required with work involving animals or large-scale activities.

For diagnostic laboratories handling primary specimens that may contain Bordetella pertussis the following resources may be consulted:

• Human Diagnostic Activities Biosafety Guideline
• Local Risk Assessment Biosafety Guideline

Section VIII – Handling and storage

Spills

Allow aerosols to settle. Wearing personal protective equipment, gently cover the spill with absorbent paper towel and apply suitable disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time with disinfectant before clean up (Canadian Biosafety Handbook).

Disposal

All materials/substances that have come in contact with the regulated materials to be completely decontaminated before they are removed from the containment zone or standard operating procedures (SOPs) to be in place to safely and securely move or transport waste out of the containment zone to a designated decontamination area/third party. This can be achieved by using decontamination technologies and processes that have been demonstrated to be effective against the regulated material, such as chemical disinfectants, autoclaving, irradiation, incineration, an effluent treatment system, or gaseous decontamination (Canadian Biosafety Handbook).

Storage

The applicable Containment Level 2 requirements for storage outlined in the Canadian Biosafety Standard are to be followed. Primary containers of regulated materials removed from the containment zone to be labelled, leakproof, impact resistant, and kept either in locked storage equipment or within an area with limited access.

Section IX – Regulatory and other information

Canadian regulatory information

Controlled activities with Bordetella pertussis require a Pathogen and Toxin licence issued by the Public Health Agency of Canada.

The following is a non-exhaustive list of applicable designations, regulations, or legislations:

• Human Pathogens and Toxins Act and Human Pathogens and Toxins Regulations
• Transportation of Dangerous Goods Act and Transportation of Dangerous Goods Regulations
• National notifiable disease (human)

Last file update

November, 2024

Prepared by

Centre for Biosecurity, Public Health Agency of Canada.

Disclaimer

The scientific information, opinions, and recommendations contained in this Pathogen Safety Data Sheet have been developed based on or compiled from trusted sources available at the time of publication. Newly discovered hazards are frequent and this information may not be completely up to date. The Government of Canada accepts no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information.

Persons in Canada are responsible for complying with the relevant laws, including regulations, guidelines and standards applicable to the import, transport, and use of pathogens in Canada set by relevant regulatory authorities, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment and Climate Change Canada, and Transport Canada. The risk classification and related regulatory requirements referenced in this Pathogen Safety Data Sheet, such as those found in the Canadian Biosafety Standard, may be incomplete and are specific to the Canadian context. Other jurisdictions will have their own requirements.

Copyright ^© Public Health Agency of Canada, 2024, Canada