Indian Ocean Basin-Wide (IOBW) Index

Syllabus: Prelims Unit II - Geography of India

• Definition: Climatological index monitoring Indian Ocean temperature variations
• Purpose: Measures sea surface temperature anomalies across Indian Ocean basin
• Applications:
• Weather pattern forecasting
• Agricultural planning
• Water resource management
• Disaster preparedness

IOBW and Dengue Correlation

• Key Findings:
• Positive index → Higher global temperatures → Increased dengue transmission
• Pre-1970: 9 countries affected
• Current: Nearly 50% of global population affected
• Stronger correlation observed in Southern Hemisphere

Seasonal Patterns

• Northern Hemisphere:
• Peak: July-October
• Coincides with summer period
• Southern Hemisphere:
• Peak: February-April
• Higher impact in tropical regions
• Brazil particularly affected

Dengue Virus Details

• Classification: Mosquito-borne viral infection
• Transmission: Through Aedes mosquitoes (primarily Aedes aegypti)
• Geographical Distribution: Tropical and subtropical regions
• Environment: Predominantly urban and semi-urban areas

Clinical Manifestations

• Primary Symptoms:
• High fever
• Severe headache
• Vomiting
• Muscle/joint pain
• Characteristic skin rash
• Severe Complications:
• Dengue hemorrhagic fever
• Blood plasma leakage
• Dengue shock syndrome (potentially fatal)

Prevention and Control

• Primary Methods:
• Mosquito control measures
• Bite prevention strategies
• Vaccination:
• Available vaccine: Dengvaxia
• Limited use: Only for seropositive individuals
• Restrictions: Safety concerns for non-infected individuals

Aedes Mosquito Characteristics

• Physical Identification:
• White leg markings
• Lyre-shaped thorax marking
• Behavioral Patterns:
• Daytime biting preference
• Peak activity: Dawn and dusk
• Breeding Habits:
• Minimal water requirement
• Difficult to control due to adaptive breeding