Category: Biology Second Paper

Virus that are naturally transmitted from vertebrates to humans are called zoonotic viruses. Zoonetic virus are:
(i) SARS Corona virus: Severe acute respiratory syndrome caused by coronavirus is called SARS. The disease is transmitted from bats to humans. In 2003, about 800 people died in China, Taiwan, Canada and other countries due to Sars disease.
(ii) MERS Corona Virus: The disease caused by Middle East respiratory syndrome coronavirus is called MERS. The disease is transmitted from bats to humans. Many people died in the Middle East due to Mars disease in 2003.
(iii) Sars Corona Virus-2: The disease caused by Severe acute respiratory syndrome coronavirus-2 is called SARS-2. The disease is globally known as COVID-19. It has been transmitted to humans from bats in Yunnan, China. Six million people died from the disease from 2019-2023. Dr. Siddiq Publications

1. Causing human diseases: Viruses cause serious diseases like human measles, measles, polio, rabies, influenza, jaundice, herpes, dengue, hepatitis, Ebola, AIDS, Sars, swine flu, cancer etc. Viruses that cause cancer in the human body are called oncogenic viruses. Cancer-causing DNA viruses are called simian and RNA viruses are called retroviruses. Human papillary virus (HPV) causes tumors, Kaposi sarcoma herpes virus (KSHV) causes skin cancer and hepatitis-C virus causes liver cirrhosis.
2. Plant Diseases: Diseases like plant mosaic, leafroll, tomato bushist, rice tungro, papaya ring spot, banana bunchy top etc. are caused by viruses. About 300 plant diseases are caused by viruses and reduce yields. Dr. Siddiq Publications
3. Cattle Diseases: Bovine Spring Disease; Foot and mouth disease in cattle, buffalo, sheep, goats, pigs, etc. and rabies in dogs and cats are caused by viruses.
4. Poultry Diseases: Poultry diseases such as avian, influenza, bird flu, swine flu etc. are caused by viruses.
5. Silkworm disease: Nuclear polyhedrosis virus (NPV) causes silkworm disease. This resulted in a disaster in the silk industry.

Chikungunya is an α-virus (RNA). Its carriers are Aedes aegypti and Aedes albopictus mosquitoes. Chikungunya was first discovered in 1952 in Tanzania, Africa. It was first caught in Bangladesh in 2008. Chikungunya spread widely in Bangladesh in April-May 2017. Chikungunya is also known as Langra Zor.

The first outbreak of Nipah virus occurred in pig farms in Malaysia in 1999. Bats are carriers of this virus. It is transmitted to the human body through the raw juice of dates. It is an RNA virus. The attack of this virus causes complications in breathing. Dr. Siddiq Publications

The disease caused by Zika virus is called Zika virus. In 1947, the Zika virus was first detected in rhesus monkeys living in the Zika forest in Uganda. It is spread by mosquitoes. In March 2016, Zika virus was detected in Chittagong district of Bangladesh. Zika virus carrier Aedes aegypti. Aedes albopictus mosquito.

Swine flu is caused by Swine Influenza virus. Swine flu is caused by influenza viruses H5N1 and H1N1. Swine flu was detected in April 2009. Humans and pigs are infected by this virus. Thousands of chickens die from this disease every year in Bangladesh. In India, 34,000 people were infected in February 2015.

Bird flu disease is caused by Avian Influenza virus (Hemagglutinin-1 Neuraminidase type-1=H1N1). In 2008, bird flu became an epidemic in Bangladesh and West Bengal. The disease affected poultry and destroyed the poultry industry. Dr. Siddiq Publications

Ebola is a deadly virus. In 1976, a farmer died of the virus on the banks of the Ebola River in Congo, Africa. The dead farmer’s eyes, nose, ears and throat were bleeding. The virus was named Ebola virus after the river. An outbreak of the Ebola virus in Zaire, Africa. In 2014-15, the Ebola outbreak killed 11,000 people, including 250 health workers, in Guinea, Sierra Leone and Liberia. Disease symptoms appear within 2-21 days.

Numerous virus have become epidemic and spread rapidly among people. Virus causing worldwide epidemics are-
(i) HIV : The virus that causes the deadly disease AIDS is HIV. It destroys human white blood cells. The body’s immune system is reduced or destroyed. In Bangladesh, the number of AIDS patients and the number of deaths are increasing.
(ii) Ebola virus: Ebola is a deadly virus. In 1976, a farmer died of the virus on the banks of the Ebola River in Congo, Africa. The dead farmer’s eyes, nose, ears and throat were bleeding. The virus was named Ebola virus after the river. An outbreak of the Ebola virus in Zaire, Africa. In 2014-15, the Ebola outbreak killed 11,000 people, including 250 health workers, in Guinea, Sierra Leone and Liberia. Disease symptoms appear within 2-21 days.
(iii) Bird flu virus: Bird flu disease is caused by Avian Influenza virus (Hemagglutinin-1 Neuraminidase type-1=H1N1). In 2008, bird flu became an epidemic in Bangladesh and West Bengal. The disease affected poultry and destroyed the poultry industry. Dr. Siddiq Publications
(iv) Swine flu virus: Swine flu is caused by Swine Influenza virus. Swine flu is caused by influenza viruses H5N1 and H1N1. Swine flu was detected in April 2009. Humans and pigs are infected by this virus. Thousands of chickens die from this disease every year in Bangladesh. In India, 34,000 people were infected in February 2015.
(v) Zika virus: The disease caused by Zika virus is called Zika virus. In 1947, the Zika virus was first detected in rhesus monkeys living in the Zika forest in Uganda. It is spread by mosquitoes. In March 2016, Zika virus was detected in Chittagong district of Bangladesh. Zika virus carrier Aedes aegypti. Aedes albopictus mosquito.
(vi) Nipah virus: The first outbreak of Nipah virus occurred in pig farms in Malaysia in 1999. Bats are carriers of this virus. It is transmitted to the human body through the raw juice of dates. It is an RNA virus. The attack of this virus causes complications in breathing. Dr. Siddiq Publications
(vii) Chikungunya: Chikungunya is an α-virus (RNA). Its carriers are Aedes aegypti and Aedes albopictus mosquitoes. Chikungunya was first discovered in 1952 in Tanzania, Africa. It was first caught in Bangladesh in 2008. Chikungunya spread widely in Bangladesh in April-May 2017. Chikungunya is also known as Langra Zor.
12. Destruction of Beneficial Microorganisms: Some virus cause economic losses by destroying beneficial microorganisms. Xymophage virus destroys yeast used in the wine or alcohol industry. Cyanophage viruses destroy blue-green algae. It reduces the amount of nitrogen in the soil. T2 bacteriophage kills E. coli bacteria that live in the human gut.

Virus that cause disease in new host species from the original host are called emerging virus. Birds are the primary host of bird flu and influenza virus and monkeys are the host of HIV. They later caused disease in the human body. In 1918-1919, more than 21 million people died of bird flu in the world. Emerging virus like HIV, SARS, Nile, Ebola etc.