PATHOGENS

Source: Hindu

Disclaimer: Copyright infringement not intended.

Context

• The World Health Organization (WHO) has introduced the term "infectious respiratory particles" (IRPs) to describe pathogens that transmit through the air.
• This move aims to address the lack of a common terminology, which was particularly challenging during the COVID-19 pandemic.
• The announcement comes after extensive consultations and reflects shared agreement among public health agencies and experts.

Details

About IRPs

• Infectious respiratory particles (IRPs) encompass particles expelled by infected individuals through breathing, talking, singing, spitting, coughing, or sneezing.
• IRPs exist on a continuous spectrum of sizes, eliminating the need for a dichotomy between aerosols and droplets.

Impact:

• Challenges During the Pandemic: Varying terminologies led to gaps in common understanding and hindered public communication and efforts to curb transmission.
• Streamlined Terminology: IRPs provide a standardized terminology to facilitate communication and response efforts across sectors and disciplines.

Examples of Pathogens Covered:

• Respiratory Infections: Examples include COVID-19, influenza, measles, Middle East Respiratory Syndrome (MERS), Severe Acute Respiratory Syndrome (SARS), and tuberculosis (TB).

Descriptors for Airborne Transmission:

• Through the Air Transmission: Descriptors include airborne transmission or inhalation, and direct deposition.
• General Characterization: The term "through the air" can be used to describe infectious diseases where transmission occurs via airborne particles.

About Pathogens

• Pathogens are microorganisms that cause disease in their host organisms.
• Types: Pathogens can be viruses, bacteria, fungi, parasites, or prions.
• Pathogenicity: Ability of a pathogen to cause disease depends on various factors, including its virulence, infectivity, and host susceptibility.

Types of Pathogens:

Viruses

• Structure: Genetic material (DNA or RNA) enclosed in a protein coat.
• Examples: Influenza virus, HIV, SARS-CoV-2.
• Mode of Transmission: Direct contact, droplets, contaminated surfaces.

Bacteria

• Structure: Single-celled organisms with various shapes (e.g., cocci, bacilli, spirilla).
• Examples: Escherichia coli, Staphylococcus aureus, Mycobacterium tuberculosis.
• Mode of Transmission: Direct contact, contaminated food/water, respiratory droplets.

Fungi

• Structure: Eukaryotic organisms with cell walls made of chitin.
• Examples: Candida albicans, Aspergillus spp., Cryptococcus neoformans.
• Mode of Transmission: Inhalation of spores, direct contact with infected surfaces.

Parasites

• Types: Protozoa (e.g., Plasmodium spp.), helminths (e.g., tapeworms, roundworms), ectoparasites (e.g., lice, ticks).
• Mode of Transmission: Ingestion of contaminated food/water, insect vectors, direct contact.

Prions

• Definition: Abnormal proteins that cause normal proteins in the brain to fold abnormally.
• Examples: Creutzfeldt-Jakob disease (CJD), bovine spongiform encephalopathy (BSE, or "mad cow" disease).
• Mode of Transmission: Ingestion of contaminated meat, genetic predisposition.

Pathogen Lifecycle:

• Transmission: Pathogens spread from one host to another through various mechanisms, including air, water, vectors (e.g., mosquitoes), and direct contact.
• Invasion: Pathogens enter the host's body through portals of entry such as mucous membranes, breaks in the skin, or ingestion.
• Colonization: Pathogens establish themselves within the host, often by adhering to host cells and tissues.
• Multiplication: Pathogens replicate within the host, leading to increased infection and tissue damage.
• Host Response: Host immune system reacts to the presence of pathogens, attempting to eliminate them through immune responses such as inflammation and antibody production.
• Pathogenesis: Pathogens cause damage to host tissues through various mechanisms, leading to the signs and symptoms of disease.
• Resolution or Chronic Infection: Depending on the effectiveness of the host immune response and the virulence of the pathogen, the infection may resolve, become chronic, or lead to the host's death.

Host-Pathogen Interactions:

• Immune Response: Innate Immunity: Non-specific immune responses that provide immediate defense against pathogens.
• Adaptive Immunity: Specific immune responses that develop over time and provide long-term protection against specific pathogens.
• Immunopathogenesis: The immune response to pathogens can sometimes cause collateral damage to host tissues, contributing to disease symptoms.
• Host Factors: Host factors such as age, genetics, and underlying health conditions influence susceptibility to infections and the severity of disease.

Emerging Pathogens:

• Zoonotic Diseases: Diseases that can be transmitted from animals to humans, such as Ebola virus disease and COVID-19.
• Antimicrobial Resistance: The ability of pathogens to resist the effects of antimicrobial drugs, posing a significant threat to public health.
• Pandemics: Global outbreaks of infectious diseases, such as the COVID-19 pandemic, highlight the ongoing threat posed by emerging pathogens.

Impact of Pathogens:

• Health: Pathogens are responsible for a wide range of infectious diseases, from mild illnesses to life-threatening conditions.
• Economic: Infectious diseases impose significant economic burdens through healthcare costs, lost productivity, and impacts on agriculture and livestock.
• Social: Outbreaks of infectious diseases can lead to social disruption, fear, and stigmatization.
• Global Health Security: Pathogens with pandemic potential pose a threat to global health security, requiring coordinated efforts for surveillance, prevention, and control.

Control and Prevention:

• Vaccination: Immunization programs can prevent many infectious diseases by stimulating the immune system to produce protective antibodies.
• Hygiene Practices: Handwashing, sanitation, and food safety measures can reduce the transmission of pathogens.
• Antimicrobial Agents: Antibiotics, antivirals, antifungals, and antiparasitic drugs can treat infections, but misuse can lead to antimicrobial resistance.
• Vector Control: Control of insect vectors can prevent the transmission of vector-borne diseases.
• Surveillance and Response: Early detection, monitoring, and rapid response to outbreaks are crucial for controlling the spread of infectious diseases.

Sources:

Hindu