Question

• How are the following diseases transmitted? African Sleeping Sickness? Staphylococcal infection of a surgical wounds? Chaga's disease? African trypanosomiasis causes infection in which body system? • How are the Eastern and Western strains of T. brucei different from one another? American trypanosomiasis causes infection in which body system? What is the most common cause of complications/death in Chagas' patients? What developmental stage does Trichomonas vaginalis lack? Why? What is the definitive (major) host for Toxoplasma gondii. • What is the most common causative agent of Neglected tropical diseases? What is the leading cause of symptoms and/or death from neglected tropical disease? Classification of Helminths into groups is primarily based on what characteristics? • What are the three stages of helminth development in order)? • What organisms are heterotrophs? Chemoheterotrophs?

Answer 1

• Transmission of Disease:

A) African sleeping sickness- This disease is mostly transmitted through the bite of an infected tsetse fly but other ways are: mother to child infection, laboratory infection with contaminated needles, through sexual contact.

B) Staphylococal infection- Staph bacteria can transmit from person to person. it can transmit by objects such as towels, clothing, door handles and remotes.

C) Chaga's Disease- The main route of transmission is the insect called triatomine bug, which can carry the trypanosoma cruzi. Other route of transmission are- oral (food borne)transmission, blood/blood products transfusion, congenital mother-to-child and organ transplantation transmission or laboratory accident transmission.

• In the first stage trypanosomes multiply in subcutaneous tissues, blood and lymph also called hemo-lymphatic stage. In the second stage the parasites cross the blood-brain barrier to infect the central nervous system also known as the neurological or meningo-encephalic stage.
• Easter strain or T. brucei rhodesiense- it causes fast onset acute trypanosomiasis in humans.
• Western strain or T. brucei gambiense- it causes slow onset chronic trypanosomiasis in humans.
• American trypanosomiasis- it affect the heart and digestive muscles, Up to 30% of patients suffer from cardiac disorders and up to 10% suffer from digestive (enlargement of the oesophagus or colon), neurological or mixed alterations.
• The most common cause of complications/death in chaga's patients is the infection which can lead to sudden death due to cardiac arrhythmias or progressive heart failure caused by the destruction of the heart muscle and its nervous system.
• Trichomonas vaginalis lacks a cystic stage. it has only trophozoite stage.
• Major host for Toxoplasma gondii are members of family Felidae- domestic cats and their relatives. unsporulated oocysts are present in the cat's feces.
• Causative agents for Neglected tropical diseases- NTDs are a group of tropical infections which are common in low-income populations in developing regions of Africa, Asia and the America. They are caused by a variety of pathogens such as viruses, bacteria, protozoa and parasitic worms.