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Zika Virus
Context:
Brazilian scientists’ research reveals a link between Zika infection and dengue severity published in the journal PLOS Neglected Tropical Diseases.
More on News:
The infection increases the likelihood of symptomatic dengue virus infection, especially with serotypes 2, 3, and 4, and the likelihood of severe dengue disease.
Key Highlights:
- Increased Risk with Prior Zika Infection
- Higher Risk: Individuals previously infected with Zika virus have a higher risk of severe dengue in later infections.
- Vaccine Implications: This connection is important for disease understanding and vaccine development.
- Mechanism of Aggravation
- Difference from Dengue: Unlike two consecutive dengue infections where the second is worse, Zika affects dengue differently.
- Higher Viral Load: Zika-related dengue infections have higher viral loads and increased inflammatory cytokines.
- T-Cell Role: Immune system T cells from the previous Zika infection cause excessive cytokine release, leading to complications like haemorrhage.
- Original Antigenic Sin
- T-Cell Response: T cells from a prior infection respond to new infections, causing an inflammatory response.
- Body Attack: These non-specific T cells attack the body’s proteins and tissues.
- Confirmation of Zika-Dengue Link
- Study Findings: The study confirms prior research showing children in Nicaragua with Zika were more likely to develop severe dengue.
- Increased Severity: Prior Zika infection significantly increases dengue severity risk.
- Clinical Implications
- Vaccine Development: Understanding Zika and dengue interactions is key for effective vaccine design.
- Public Health Awareness: Health authorities should educate the public about the combined threat of Zika and dengue.
About Zika:
- A mosquito-borne virus primarily spread by the Aedes species of mosquito.
- Discovery: First identified in Uganda’s Zika Forest in 1947.
- Transmission: Besides mosquito bites, it can be transmitted through sexual contact, blood transfusions, and from mother to foetus.
- Symptoms
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- Common Symptoms: Fever, rash, joint pain, and conjunctivitis (red eyes).
- Other Symptoms: Muscle pain, headache, and malaise.
- Duration: Symptoms typically last from several days to a week.
- Severity: Most infections are mild, and many people do not exhibit symptoms.
- Complications:
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- Pregnancy Risks: Zika virus can cause severe birth defects, including microcephaly (a condition where a baby’s head is smaller than expected).
- Neurological Effects: Associated with Guillain-Barré syndrome, a rare condition where the immune system attacks the nerves.
- Prevention:
- Mosquito Control: Use insect repellent, wear long sleeves and pants, and use mosquito nets.
- Travel Precautions: Avoid travelling to areas with ongoing Zika outbreaks, especially for pregnant women.
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- Safe Sex Practices: Use condoms or abstain from sex to prevent sexual transmission.
- Diagnosis and Treatment:
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- Diagnosis: Confirmed through blood or urine tests that detect the virus’s genetic material or antibodies.
- Treatment: No specific treatment or vaccine is available. Symptomatic treatment includes rest, fluids, and medications like acetaminophen to reduce fever and pain.
- Public Health Impact:
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- Epidemics: Notable outbreaks occurred in the Americas, Southeast Asia, and the Pacific Islands.
- Surveillance: Continual monitoring and research are critical to control and prevent outbreaks.
- Education: Public awareness campaigns are essential to inform people about prevention methods and risks.