Tibrovirus

Key takeaways

Tibrovirus belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Tibrovirus to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tibrovirus from memory before moving on to harder problems.

Reference excerpt

Tibrovirus is a genus of viruses in the family Rhabdoviridae, order Mononegavirales. There are 9 members of the genus. Tibroviruses have been isolated from biting midges, cattle, and humans. None of the tibroviruses, except for Bas-Congo virus, have been associated with any diseases.

Genus members Bas-Congo virus (BASV, Tibrovirus congo) was discovered in 2009 in the Democratic Republic of Congo in a blood sample collected from a 32-year-old male who survived a severe illness resembling hemorrhagic fever. BASV could not be isolated from the patient’s sample has not been established as a human pathogen. Beatrice Hill virus (BHV, Tibrovirus beatrice) was isolated from a pool of biting midges (Culicoides peregrinus) in 1984 in Northern Territory, Australia. BHV is poorly characterized and serological studies to assess its prevalence have not been carried out. Bivens arm virus (BAV) was isolated in 1981-1982 from a pool of biting midges in Florida. Anti-BAV antibodies have been detected in a variety of animals, including cattle, throughout Florida and the Caribbean. There is no evidence of human infection or any disease associated with BAV. Coastal Plains virus (CPV, Tibrovirus coastal) was discovered in 1981 in Northern Territory, Australia in the blood of a healthy, asymptomatic steer. No anti-CPV antibodies have ever been detected in humans and no disease has been associated with CPV. Ekpoma virus 1 (EKV-1, Tibrovirus alphaekpoma) was discovered in 2015 in a blood sample collected from a healthy, 45-year-old woman living in Ekpoma, Nigeria. EKV-1 was present in her blood at 4.5 million RNA copies/mL suggesting robust replication. Experiments using a recombinant vesicular stomatitis virus expressing the EKV-1 envelope glycoprotein indicate EKV-1 has very broad tropism and can efficiently enter nearly all types of human cells. EKV-1 could not be isolated from the patient’s blood sample and live replication-competent virus is not available. Ekpoma virus 2 (EKV-2, Tibrovirus betaekpoma) was discovered in 2015 in a blood sample collected from a healthy, 19-year-old woman living in Ekpoma, Nigeria. EKV-2 was present in her blood at 45,000 RNA copies/mL suggesting modest replication. Experiments using a recombinant vesicular stomatitis virus expressing the EKV-2 envelope glycoprotein indicate EKV-2 has very broad tropism similar to EKV-1. EKV-2 also could not be isolated from the patient’s blood sample and live replication-competent virus is not available. Mundri virus (MUNV, Tibrovirus mundri) Sweetwater branch virus (SWBV, Tibrovirus sweetwater) was isolated along with BAV from pools of biting midges in Florida in 1981-1982. Like BAV, SWBV exposure in various animals is likely widespread. There is no evidence of human exposure or any disease associated with the virus. Tibrogargan virus (TIBV, Tibrovirus tibrogargan), the first tibrovirus discovered, was isolated from a pool of biting midges (Culicoides brevitarsis) in 1976 in Peachester, Australia. TIBV appears to be widespread among cattle in Australia. A survey of more than 3,000 cattle found many herds were 100% seropositive. TIBV infection of humans has not been reported. TIBV is an orphan virus and not associated with any disease. Experimental infections of cattle produced viremia, but no observable signs of illness.

Transmission BHV, BAV, SWBV and TIBV were isolated from biting midges, suggesting that midges are the major arthropod vector for these viruses. It is not known how BASV, EKV-1 and EKV-2 are transmitted.

Genetic divergence Tibroviruses are highly divergent. For example, overall amino acid homology among the human-associated tibroviruses (i.e. BASV, EKV-1 and EKV-2) ranges from 33% - 39%.

Morphology Tibrovirus virions are enveloped, but only the morphology of Tibrogargan virus and Sweetwater branch virus have been observed by electron microscopy.

Genome Tibrovirus genomes are single-stranded, negative-sense RNA molecules approximately 13 kb in length. The genome encodes for the typical five proteins found in all rhabdoviruses: nucleocapsid (N), phosphoprotein (P), matrix (M), glycoprotein (G), and polymerase (L). However, there are three additional genes, U1-U3, that encode for proteins of unknown function.

Life cycle Viral replication is cytoplasmic. Entry into the host cell is achieved by attachment of the viral G glycoproteins to host receptors, which mediate clathrin-mediated endocytosis. Replication follows the negative-stranded RNA virus replication model. Negative stranded RNA virus transcription, using polymerase stuttering is the method of transcription. The virus exits the host cell by budding, and tubule-guided viral movement.

References

External links Viralzone: Tibrovirus ICTV

Illustrations

Worked examples

Example 1 — a first encounter with Tibrovirus

Start with the simplest possible case. Write down what Tibrovirus claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Tibrovirus before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Tibrovirus ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Tibrovirus

In research: Tibrovirus appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Tibrovirus in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Tibrovirus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Rhabdoviridae, Virus genera, so understanding it makes those chapters shorter.
In everyday life: Look for Tibrovirus outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Tibrovirus in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Tibrovirus means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Tibrovirus out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tibrovirus in simple terms?

Tibrovirus is a genus of viruses in the family Rhabdoviridae, order Mononegavirales. There are 9 members of the genus.

Why does Tibrovirus matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Tibrovirus?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Tibrovirus.