Category: Biology Second Paper Lecture Sheet

Cholera is caused by bacteria called Vibrio cholerae. Scientist Robert Koch was the first to discover the germ. Felix Archimedes Pochet first described this bacterium in 1849.

Cholera is a waterborne infectious disease. It is called Olautha disease. Olautha means frequent defecation and vomiting. The prevalence of this disease is highest in the Indian subcontinent. In Asia, Latin America and Africa, the disease appeared in epidemic form. Worldwide, 3–5 million people were infected with cholera each year and about 0.1 million died.

Cause of cholera disease
Cholera is a waterborne infectious disease. It is called Olautha disease. Olautha means frequent defecation and vomiting. The prevalence of this disease is highest in the Indian subcontinent. In Asia, Latin America and Africa, the disease appeared in epidemic form. Worldwide, 3–5 million people were infected with cholera each year and about 0.1 million died.
Cause of Cholera: Cholera is caused by bacteria called Vibrio cholerae. Scientist Robert Koch was the first to discover the germ. Felix Archimedes Pochet first described this bacterium in 1849.

Transmission or spread of cholera disease
1. Cholera is transmitted through contaminated water.
2. Cholera spreads rapidly in areas that lack proper sanitation and clean drinking water.
3. Germs are spread through the patient’s excreta.
4. Cholera bacteria can survive in coastal areas and brackish water.
5. Cholera bacteria live in fish, crabs, oysters, snails, shrimps, hard bony fish, etc.
6. Germs spread through dishes used by the patient.
7. In the mucosa of the patient’s small intestine, this bacterium secretes a toxic toxin called enterotoxin or collagen. These toxins are excreted in the feces and spread to the environment.

Symptoms of Cholera
Symptoms of cholera disease appear within 1-5 days after the germs enter the human intestine. The symptoms of this disease are:
1. In this disease, the patient has diarrhea and stools with a fishy smell.
2. The toilet is like washing water. Blood is seen in the stool.
3. 10-15 liters of water is lost from the body and dehydration occurs. It is called Dehydration.
4. Constant vomiting and loss of sodium ions in the body.
5. The body temperature rises, restlessness appears, and the body cools down to 95-96 degrees Fahrenheit.
6. Urination may stop. May cause urinary incontinence.
7. Frequent great thirst for water, but cannot retain water.
8. Cramps in the abdominal muscles, cramps and spasms.
9. Blood thickens and blood pressure drops to 70-90 mmHg.
10. The eyes become sunken, the eyes become sunken, and gray spots appear around the eyes.
11. The patient’s skin becomes dry and loose, the face becomes dull, the body pale.
12. Enterotoxins or collagens released from bacterial cells cause lesions in the intestinal wall.
13. The pulse is very slow. The heart may stop working. Electrolyte balance is disturbed.
14. Cramps occur in the muscles of the hands and feet, and cramps occur.
15. Decreased blood flow leads to lack of oxygen in the brain. The patient becomes unconscious and may die.
16. There is more heat in the anus. Pain in the anus.
17. Fingertips turn blue.

Cure for cholera
1. The patient should eat saline food frequently. It will remove water shortage. This is called rehydration.
2. A cholera patient should be fed plenty of canned water and liquid food (rice gruel). It will fill the electrolyte deficiency quickly.
3. If saline administration is not possible, intravenous fluids (IV fluids) should be administered to the patient.
4. The patient’s body should be kept elevated on a comfortable bed.
5. The patient can be treated with tetracycline, cotimoxazole, erythromycin, sulfamethoxazole, ciprofloxacin etc.
6. Care should be taken to ensure that the patient is not debilitated or that blood pressure is normal.
7. Care should be taken to prevent dehydration in the patient’s body.

Cholera prevention
1. Always drink clean water. Water should be boiled or filtered.
2. Stale, rotten and open food should be avoided. Eating unprocessed raw vegetables should be avoided.
3. Secondary infection occurs through fleas from the vomitus of the patient. So food should always be covered.
4. Wash your hands thoroughly with soap or water before eating and after going to the toilet.
5. Garbage should be disposed of in designated areas. The environment should be kept clean.
6. The patient’s clothes and bedding should be boiled and dried in the sun.
7. The patient should be isolated. The patient’s stool should be cleaned.
8. Caregivers and carriers of the disease should be identified and treated.
9. Cholera vaccine should be given. An oral cholera vaccine is currently available.
10. Everyone should be made aware about hygiene.

Environmental importance in the spread of cholera
1. Stale, rotten and open food is a suitable medium for the spread of cholera. Cholera is more prevalent in environments where people are accustomed to stale, rotten and open food.
2. Contaminated water is a carrier of cholera. Cholera is more prevalent in environments where people drink contaminated water.
3. Cholera spreads where garbage is thrown.
4. Cholera is more likely to occur in people who use sick clothes and bedding.
5. If you do not wash your hands with soap or ash before eating and after using the toilet, the disease can be transmitted.
6. The disease is spread by the equipment used in the treatment of the patient.

1. Food shortage: If rice leaf blight disease occurs in epidemic form, rice yield will decrease. Paddy cultivation will decrease a lot. The food needs of the growing population will not be met. There will be extreme food shortage in the country.
2. Economic collapse: If rice disease becomes an epidemic in the country, the production of other crops will be greatly affected. There will be a slowdown in business. Family and national economy will be greatly affected. As a result, the economy will collapse.
3. Agricultural disaster: If rice leaf blight becomes epidemic, rice and other crops will be greatly affected. Paddy cultivation will be stopped for 1-3 years in certain areas. As a result there will be agricultural disaster.
4. Dissatisfaction of farming families: If rice diseases spread in epidemic form, the yield of rice will decrease. Rice production will decrease. Paddy cultivation will be stopped. The agricultural families will be in financial crisis. As a result, there will be widespread dissatisfaction among the populous agricultural families.
5. Forestry Disasters: Rice diseases can spread along with other plant diseases. Different plants can be affected. Plantation operations will be hampered due to disease outbreaks. Tree planting programs may be discontinued. As a result, there will be a forest disaster.
6. Import of food from abroad: Rice production will decrease due to epidemic. Paddy cultivation will stop. There will be food shortage in the country. Food needs to be imported from abroad to meet the food demand.
7. Stop export of goods: Panic will be created in the country and neighboring countries due to the epidemic. Pathogens can spread with different products. Diseases are likely to spread from one area to another and from one country to another. Therefore, the export of goods abroad will be stopped.
8. Stopping industrial production: The raw material of industry is agricultural products. Due to the rice epidemic, the supply of raw materials to the industry will be severely disrupted. As a result, industrial production may stop due to lack of raw materials.
9. Increase in unemployment: Rice production will stop due to epidemics. Other agricultural production will decrease. There will be a slowdown in domestic and foreign trade. Industrial production will decrease. As a result, unemployment will increase.
10. Weed Outbreaks: Crop production can be stopped due to epidemics. Weeds will continue to grow naturally. Weeds will produce lots of seeds. This will greatly increase the prevalence of weeds.

1. Healthy, vigorous, disease-free and disease-resistant varieties should be used. High yielding varieties resistant to leaf blight are Xa4, Xa5, Xa13, Xa21, Xa33, Xa38 etc.
2. The seeds should be treated with fungicide before sowing. The seeds should be treated with bleaching powder (100 mg/ml) and zinc sulphate (2%).
3. Spraying streptocycline on diseased leaves is beneficial.
4. Weeds and garbage on the land should be destroyed or burnt. Paddy straw and other growing plants should be removed.
5. The land should be well dried before sowing.
6. Phenyl sulfuric acetate and m. 10-20 liters of Chloramphenicol should be applied.
7. Water drainage should be arranged.
8. Seed beds should be made on high ground. Plant to plant distance and line to line distance should be scientific.
9. Disinfect the soil by spreading copper oxychloride.
10. Chlorine or bleaching powder should be applied with irrigation water.
11. Nitrogen fertilizers should be applied in the right amount at the right time. Do not overdose.
12. Diseased rice plants should be uprooted and burnt.
13. Seed borne infection is prevented by soaking in 0.1% Sirisan solution for 8 hours before sowing.
14. Quarantine procedures should be adopted.

Rice leaf blight disease symptoms appear 5-6 weeks after infection. The symptoms are:
1. Disease symptoms on rice leaves
(i) In the initial stage, wet, semi-transparent and elongated spots are formed on the leaves.
(ii) Wet spots 5-10 mm long are seen on petioles, main veins and margins.
(iii) The spots coalesce to form white or yellow striped spots.
(iv) The spots become progressively yellow and gray and become large in size. It is called Kresek.
(v) Diseased leaves gradually dry up and curl up.
(vi) Affected areas appear wavy.
(vii) White sticky sap accumulates on the leaves.
(viii) Milk-colored sticky droplets accumulate on the leaves in the early morning and later dry up to form small orange beads.
(ix) Diseased leaves dry up quickly and plants die.

2. Disease symptoms in rice seeds
(i) Attack of the disease occurs at the time of emergence of the rice grain.
(ii) The glume of paddy becomes scorched by water retention and becomes straw-like in colour.
(iii) Water-soaked small and round lesions are seen on infected paddy shoots.
(iv) Diseased paddy is sterile, the paddy is stunted and yield is reduced by 60%.
(v) Diseased rice grains do not bear fruit.

1. In favorable conditions, the spores of this bacteria survive in the soil for many days.
2. The disease attacks the next crop through rice weed and weed. Subsists on grasses and wild rice as alternative feeders.
3. Bacterial spores can survive in canal water during summer.
4. Bacteria enter the host through plant wounds and hydathodes. Later enters leaf veins.
5. This germ spreads with the help of wind and rain water.
6. This germ spread in the field through ground water.
7. High temperature (25-30°C), high water vapor and rainfall are conducive to disease transmission.
8. The disease is spread by air flow and excess nitrogen in the soil.

Xanthomonas oryzae is a bacterium called leaf blight disease of rice.
It is a rod-shaped bacterium. They are gram negative bacteria. They do not produce spores. Their cells do not have capsules. They have only one flagellum.

Decaying or dying or wilting of plant leaves, flowers, fruits and stem tissue is called blight. Blight disease of rice is called leaf burn disease or collapse disease. Farmers in Japan were the first to discover the disease. In Japan, this disease is known as white rice disease. In Bangladesh in 1986, the existence of this disease was detected in Ropa Aman rice. In 1908, Japanese scientist Takaeshi proved that it is a bacterial disease. This disease reduces rice production by 22,000-110,000 tons per year in Japan.

Decaying or dying or wilting of plant leaves, flowers, fruits and stem tissue is called blight. Blight disease of rice is called leaf burn disease or collapse disease. Farmers in Japan were the first to discover the disease. In Japan, this disease is known as white rice disease. In Bangladesh in 1986, the existence of this disease was detected in Ropa Aman rice. In 1908, Japanese scientist Takaeshi proved that it is a bacterial disease. This disease reduces rice production by 22,000-110,000 tons per year in Japan.

Cause of rice blight disease: Xanthomonas oryzae is a bacterium called leaf blight disease of rice.
It is a rod-shaped bacterium. They are gram negative bacteria. They do not produce spores. Their cells do not have capsules. They have only one flagellum.

Infection or spread of rice leaf blight disease
1. In favorable conditions, the spores of this bacteria survive in the soil for many days.
2. The disease attacks the next crop through rice weed and weed. Subsists on grasses and wild rice as alternative feeders.
3. Bacterial spores can survive in canal water during summer.
4. Bacteria enter the host through plant wounds and hydathodes. Later enters leaf veins.
5. This germ spreads with the help of wind and rain water.
6. This germ spread in the field through ground water.
7. High temperature (25-30°C), high water vapor and rainfall are conducive to disease transmission.
8. The disease is spread by air flow and excess nitrogen in the soil.

Rice Leaf Blight Disease Symptoms: Rice leaf blight disease symptoms appear 5-6 weeks after infection. The symptoms are:
1. Disease symptoms on rice leaves
(i) In the initial stage, wet, semi-transparent and elongated spots are formed on the leaves.
(ii) Wet spots 5-10 mm long are seen on petioles, main veins and margins.
(iii) The spots coalesce to form white or yellow striped spots.
(iv) The spots become progressively yellow and gray and become large in size. It is called Kresek.
(v) Diseased leaves gradually dry up and curl up.
(vi) Affected areas appear wavy.
(vii) White sticky sap accumulates on the leaves.
(viii) Milk-colored sticky droplets accumulate on the leaves in the early morning and later dry up to form small orange beads.
(ix) Diseased leaves dry up quickly and plants die.

2. Disease symptoms in rice seeds
(i) Attack of the disease occurs at the time of emergence of the rice grain.
(ii) The glume of paddy becomes scorched by water retention and becomes straw-like in colour.
(iii) Water-soaked small and round lesions are seen on infected paddy shoots.
(iv) Diseased paddy is sterile, the paddy is stunted and yield is reduced by 60%.
(v) Diseased rice grains do not bear fruit.

Treatment of rice leaf blight disease
1. Healthy, vigorous, disease-free and disease-resistant varieties should be used. High yielding varieties resistant to leaf blight are Xa4, Xa5, Xa13, Xa21, Xa33, Xa38 etc.
2. The seeds should be treated with fungicide before sowing. The seeds should be treated with bleaching powder (100 mg/ml) and zinc sulphate (2%).
3. Spraying streptocycline on diseased leaves is beneficial.
4. Weeds and garbage on the land should be destroyed or burnt. Paddy straw and other growing plants should be removed.
5. The land should be well dried before sowing.
6. Phenyl sulfuric acetate and m. 10-20 liters of Chloramphenicol should be applied.
7. Water drainage should be arranged.
8. Seed beds should be made on high ground. Plant to plant distance and line to line distance should be scientific.
9. Disinfect the soil by spreading copper oxychloride.
10. Chlorine or bleaching powder should be applied with irrigation water.
11. Nitrogen fertilizers should be applied in the right amount at the right time. Do not overdose.
12. Diseased rice plants should be uprooted and burnt.
13. Seed borne infection is prevented by soaking in 0.1% Sirisan solution for 8 hours before sowing.
14. Quarantine procedures should be adopted.

What will be the disaster if there is an epidemic of rice leaf blight?
1. Food shortage: If rice leaf blight disease occurs in epidemic form, rice yield will decrease. Paddy cultivation will decrease a lot. The food needs of the growing population will not be met. There will be extreme food shortage in the country.
2. Economic collapse: If rice disease becomes an epidemic in the country, the production of other crops will be greatly affected. There will be a slowdown in business. Family and national economy will be greatly affected. As a result, the economy will collapse.
3. Agricultural disaster: If rice leaf blight becomes epidemic, rice and other crops will be greatly affected. Paddy cultivation will be stopped for 1-3 years in certain areas. As a result there will be agricultural disaster.
4. Dissatisfaction of farming families: If rice diseases spread in epidemic form, the yield of rice will decrease. Rice production will decrease. Paddy cultivation will be stopped. The agricultural families will be in financial crisis. As a result, there will be widespread dissatisfaction among the populous agricultural families.
5. Forestry Disasters: Rice diseases can spread along with other plant diseases. Different plants can be affected. Plantation operations will be hampered due to disease outbreaks. Tree planting programs may be discontinued. As a result, there will be a forest disaster.
6. Import of food from abroad: Rice production will decrease due to epidemic. Paddy cultivation will stop. There will be food shortage in the country. Food needs to be imported from abroad to meet the food demand.
7. Stop export of goods: Panic will be created in the country and neighboring countries due to the epidemic. Pathogens can spread with different products. Diseases are likely to spread from one area to another and from one country to another. Therefore, the export of goods abroad will be stopped.
8. Stopping industrial production: The raw material of industry is agricultural products. Due to the rice epidemic, the supply of raw materials to the industry will be severely disrupted. As a result, industrial production may stop due to lack of raw materials.
9. Increase in unemployment: Rice production will stop due to epidemics. Other agricultural production will decrease. There will be a slowdown in domestic and foreign trade. Industrial production will decrease. As a result, unemployment will increase.
10. Weed Outbreaks: Crop production can be stopped due to epidemics. Weeds will continue to grow naturally. Weeds will produce lots of seeds. This will greatly increase the prevalence of weeds.