5.5.4 Cotton Leaf Curl Disease

Definition: Cotton leaf curl disease (CLCuD) is a serious disease of cotton.

• Cause: Begomoviruses
• Transmission: Transmitted by the whitefly
• Symptoms: Initially characterized by a deep downward cupping of the youngest leaves; followed by development of cup-shaped, leaf-like structures
• Treatment and Prevention: Control of CLCuD is mainly based on insecticide treatments against the insect vector

Summary Table of Viral Diseases

Intermediate Level

Hepatitis in Detail

Herpes in Detail

Poliomyelitis in Detail

Cotton Leaf Curl Disease in Detail

Important Points

• 1. Hepatitis is generally characterized as inflammation of the liver including other symptoms.
• 2. It is generally caused by viral infection or rarely due to toxicity of drugs and certain other causes.
• 3. It may present in acute (recent infection, relatively rapid onset) or chronic (slowly progressing) forms.
• 4. The most common causes of viral hepatitis are Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis D, and Hepatitis E.
• 5. Hepatitis A:
• - Cause: HAV
• - Transmission: Faecal-oral route
• - Symptoms: Fever, loss of appetite, nausea, vomiting, jaundice, dark urine, pale faeces
• - Treatment: No antiviral therapy
• - Prevention: Active immunization with a vaccine containing inactivated HAV; proper hygiene
• 6. Hepatitis B:
• - Cause: HBV
• - Transmission: Blood, sexual contact, prenatally from mother to newborn
• - Symptoms: Similar to hepatitis A
• - Treatment: Alpha interferon is effective against HBV
• - Prevention: Vaccine is highly effective; all blood transfusion should be screened
• 7. Hepatitis C:
• - Cause: HCV
• - Transmission: Only via blood
• - Symptoms: Similar to hepatitis B
• - Treatment: Combination of alpha interferon and ribavirin
• - Prevention: No vaccine; blood transfusion should be screened
• 8. Hepatitis D:
• - Cause: HDV (viroid)
• - Transmission: Blood or serum transfusions
• - Symptoms: As in hepatitis B but more severe
• - Treatment and Prevention: Same as HBV
• 9. Hepatitis E:
• - Cause: HEV
• - Transmission: Faecal-oral route
• - Treatment and Prevention: No antiviral treatment and vaccine; proper hygiene
• 10. Herpes simplex is a superficial viral infection characterized by one or more painful, fluid-filled sores or blisters appearing on the skin or epithelium of outer openings of the body.
• 11. Oral Herpes:
• - Cause: HSV-1
• - Transmission: Oral secretions (saliva) or physical contact
• - Symptoms: Blisters on lips or around the mouth
• - Treatment: Antiviral drugs
• - Prevention: Avoid contact with affected area
• 12. Genital Herpes:
• - Cause: HSV-2
• - Transmission: Sexual contact
• - Symptoms: Sores on penis, vagina, buttocks, or anus
• - Treatment: Antiviral drugs
• - Prevention: Avoid contact with affected area
• 13. Poliomyelitis:
• - Cause: Poliovirus
• - Transmission: Faecal-oral route
• - Replication: Oropharynx, intestinal tract, blood, CNS, motor neurons
• - Symptoms: Paralysis
• - Treatment: No antiviral therapy; physiotherapy
• - Prevention: Killed vaccine (IPV), live attenuated vaccine (OPV)
• 14. Cotton Leaf Curl Disease:
• - Cause: Begomoviruses
• - Transmission: Whitefly
• - Symptoms: Deep downward cupping of youngest leaves; cup-shaped, leaf-like structures
• - Treatment and Prevention: Insecticide treatments against the insect vector

Remember

• - Hepatitis = liver inflammation
• - Hepatitis A = HAV; faecal-oral; vaccine
• - Hepatitis B = HBV; blood, sexual, prenatal; vaccine
• - Hepatitis C = HCV; blood; no vaccine
• - Hepatitis D = HDV; blood; requires HBV
• - Hepatitis E = HEV; faecal-oral; hygiene
• - **Herpes** = blisters
• - Oral Herpes = HSV-1; saliva, contact
• - Genital Herpes = HSV-2; sexual contact
• - Polio = poliovirus; faecal-oral; paralysis; vaccines (IPV, OPV)
• - Cotton Leaf Curl = begomoviruses; whitefly; cupping of leaves

Common Mistakes

• 1. Confusing the different types of hepatitis – Each type has a different cause, transmission, and prevention.
• 2. Thinking hepatitis A and E are blood-borne – Hepatitis A and E are faecal-oral.
• 3. Thinking hepatitis B and C are food-borne – Hepatitis B and C are blood-borne.
• 4. Confusing HSV-1 and HSV-2 – HSV-1 = oral herpes; HSV-2 = genital herpes.
• 5. Thinking herpes can be cured – Herpes is a lifelong infection; antiviral drugs control symptoms.
• 6. Thinking polio is eradicated – Polio is near eradication but still endemic in some countries.
• 7. Confusing the polio vaccines – IPV = killed; OPV = live, attenuated.
• 8. Thinking CLCuD is caused by a virus that infects humans – CLCuD is a plant disease.
• 9. Forgetting the vector for CLCuD – The vector is the whitefly.
• 10. Thinking all hepatitis viruses are the same – They are different viruses with different properties.
• 11. Forgetting the treatment for hepatitis C – Interferon + ribavirin.
• 12. Thinking hepatitis D is independent – Hepatitis D requires HBV for replication.

Quick Revision

• Hepatitis is generally characterized as inflammation of the liver including other symptoms.
• It is generally caused by viral infection or rarely due to toxicity of drugs and certain other causes.
• It may present in acute (recent infection, relatively rapid onset) or chronic (slowly progressing) forms.
• The most common causes of viral hepatitis are Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis D, and Hepatitis E.
• Hepatitis A:
• Cause: HAV
• Transmission: Faecal-oral route
• Symptoms: Fever, loss of appetite, nausea, vomiting, jaundice, dark urine, pale faeces
• Treatment: No antiviral therapy
• Prevention: Active immunization with a vaccine containing inactivated HAV; proper hygiene
• Hepatitis B:
• Cause: HBV
• Transmission: Blood, sexual contact, prenatally from mother to newborn
• Symptoms: Similar to hepatitis A
• Treatment: Alpha interferon is effective against HBV
• Prevention: Vaccine is highly effective; all blood transfusion should be screened
• Hepatitis C:
• Cause: HCV
• Transmission: Only via blood
• Symptoms: Similar to hepatitis B
• Treatment: Combination of alpha interferon and ribavirin
• Prevention: No vaccine; blood transfusion should be screened
• Hepatitis D:
• Cause: HDV (viroid)
• Transmission: Blood or serum transfusions
• Symptoms: As in hepatitis B but more severe
• Treatment and Prevention: Same as HBV
• Hepatitis E:
• Cause: HEV
• Transmission: Faecal-oral route
• Treatment and Prevention: No antiviral treatment and vaccine; proper hygiene
• Herpes simplex is a superficial viral infection characterized by one or more painful, fluid-filled sores or blisters appearing on the skin or epithelium of outer openings of the body.
• Oral Herpes:
• Cause: HSV-1
• Transmission: Oral secretions (saliva) or physical contact
• Symptoms: Blisters on lips or around the mouth
• Treatment: Antiviral drugs
• Prevention: Avoid contact with affected area
• Genital Herpes:
• Cause: HSV-2
• Transmission: Sexual contact
• Symptoms: Sores on penis, vagina, buttocks, or anus
• Treatment: Antiviral drugs
• Prevention: Avoid contact with affected area
• Poliomyelitis:
• Cause: Poliovirus
• Transmission: Faecal-oral route
• Replication: Oropharynx, intestinal tract, blood, CNS, motor neurons
• Symptoms: Paralysis
• Treatment: No antiviral therapy; physiotherapy
• Prevention: Killed vaccine (IPV), live attenuated vaccine (OPV)
• Cotton Leaf Curl Disease:
• Cause: Begomoviruses
• Transmission: Whitefly
• Symptoms: Deep downward cupping of youngest leaves; cup-shaped, leaf-like structures
• Treatment and Prevention: Insecticide treatments against the insect vector

60-Second Revision

• Hepatitis = liver inflammation
• Hepatitis A = HAV; faecal-oral; vaccine
• Hepatitis B = HBV; blood, sexual, prenatal; vaccine
• Hepatitis C = HCV; blood; no vaccine
• Hepatitis D = HDV; blood; requires HBV
• Hepatitis E = HEV; faecal-oral; hygiene
• **Herpes** = blisters
• Oral Herpes = HSV-1; saliva, contact
• Genital Herpes = HSV-2; sexual contact
• Polio = poliovirus; faecal-oral; paralysis; vaccines (IPV, OPV)
• Cotton Leaf Curl = begomoviruses; whitefly; cupping of leaves
• Warning: Each type of hepatitis has a different cause, transmission, and prevention. Hepatitis A and E are faecal-oral. Hepatitis B and C are blood-borne. HSV-1 causes oral herpes; HSV-2 causes genital herpes. Herpes is a lifelong infection. Polio is near eradication but still endemic in some countries. CLCuD is a plant disease caused by begomoviruses and transmitted by whitefly.