Trypanosoma - Diagram, Morphology and Diseases

Introduction

Trypanosoma are unicellular, parasitic and flagellated protozoans that belong to the family Kinetoplastea. The word Trypanosoma has been taken from the Greek words trypano (borer) and soma (body) because of their corkscrew-like motion. All the members belonging to the zooflagellate, protozoan Trypanosoma genus are referred to as trypanosomes.

They are obligatory parasites, meaning they require at least one host to complete their life cycle. Some species are heteroxenous that require more than one host to complete their life cycle. They are mostly transmitted by blood feeding invertebrates.

Classification

Well-Labelled Diagram of Trypanosoma

Morphology and Life Cycle

• They are unicellular, parasitic and flagellated protozoans.
• The mitochondrial genome of trypanosomes is known as kinetoplast DNA or kDNA. It is made up of catenated circles and minicircles and requires a different set of proteins during cell division.
• Trypanosoma exist in two different types and that have different types of life cycles – stercorarian and salivarian species.
• The stercoraria trypanosoma species first infects a triatomine kissing bug during a blood meal and develops in the posterior gut of the insect. It is then released in the faeces followed by deposition of the skin of the host. The trypanosoma then penetrates in the body of the host and causes infection.
• The salivarian species develops in the anterior gut of Tsetse fly and is transmitted to the host by insect feed.
• The trypanosomes undergo a series of morphological changes during their transition from invertebrates to vertebrates.
• Trypomastigote is identified by their flagella that is attached to the body by an undulating membrane and the kinetoplast lies in the posterior portion of the body. This form of trypanosomes is found in the vertebrate host but is developed in the invertebrate host.
• Amastigote is another form of Trypanosoma that is identified by no visible external flagella or cilia. It is the intracellular form that is found during the replication phase of the organism.

Common Species and Diseases Caused

1. Trypanosoma brucei

It is a parasitic species that causes vector borne disease in vertebrate animals that is transmitted by the Tsetse fly. It causes African trypanosomiasis, commonly known as sleeping sickness whereas in animals it causes animal trypanosomiasis.

The insect vector Tsetse fly picks up the protozoa during a blood meal and then undergoes various morphological changes as it transitions from insects to mammals. Common symptoms of this disease include itchiness, headache and joint pains which slowly advances into numbness, poor coordination and trouble sleeping.

2. Trypanosoma cruzi

They are parasitic euglenoids that feed on blood and lymph. It causes Chagas disease in humans, brucellosis in cattle, covering sickness and surra in horses. The vector for transmission of this disease is kissing bugs that infect the host by a simple insect bite.

Early symptoms of the disease include swollen lymph nodes, headaches and swelling at the site of the bite which advances into chronic infections.

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