Shrimp white spot syndrome

Hello everyone and welcome back! Muppet treasure island is a movie I like a lot (you should check it out if you haven’t already haha), and in it there’s reference to the ‘black spot’. To a pirate, the black spot was a bad sign, and the recipient of said spot knew that they probably wouldn’t be alive for much longer. Well, today I’m going to talk about another spot, that is just as bad of a sign for some shrimp.

Whispovirus, a.k.a white spot, is the only genus of virus in the family Nimaviridae. This virus contains DNA and actually, a group (or complex) of viruses, called the Whitespot Syndrome Baculovirus complex, causes the disease called white spot syndrome. This virus particularly infects a specific type of shrimp (penaeid shrimp), although it can also infect other types of crustaceans. Characteristic white spots are created on the shell of the shrimp…and they also get sluggish and lose their appetite. We care about penaeid shrimp because many of them are consumed as food around the world, and a lot of money passes through many hands because of this industry. If you are a student, can you quickly research what other type of crustacean this virus affects?

In the early 1990s, there were reports of huge white spot outbreaks in Taiwan and China, causing a big problem for the shrimp farming business. Several other countries such as the United States, Saudi Arabia, India and Japan have all seen instances of outbreaks, with reports being made as recently as 2016 in Australia. What further makes this virus such a problem is that there is no current treatment for the disease, it is very contagious, it kills all the shrimp in a given location, and it does it fast! So fast in fact, that all the shrimp in a given shrimp farm could be wiped out within days!!

Well then…what can we do about this problem you ask? Prevention is key. So, it appears that penaeid shrimp like a relaxed life (like some people I know…haha), so, it’s a good idea to keep reared shrimp away from environmental stressors, which include big changes in temperature or salt content, or exposure to bacterial infections. Disinfectants can be used, and farmers are careful to avoid instances of contamination. Overall, it seems as though much research still needs to be done (hint hint to any budding scientists out there), to help discover treatments for shrimp white spot syndrome.

Take care until next time, and happy Earth Day! 😊

Follow the links to read more on white spot syndrome, and Penaeidae. Credit is given for use of images of white spot diseased individual, Mahajamba shrimp farm, and shrimp with sauce cartoon.

 

Wilting away

Hello everyone and welcome back! A couple months ago a friend gave me a plant, that I’ve now named Eugene (don’t question it too much…the plant just looked like a Eugene haha!), and ‘he’ seems to be doing quite well and suffers from no bacterial infections (…that I know of!). However, there are some plant species that are susceptible to bacterial infection by the gram-negative pathogen Ralstonia solanacearum, and I’ll talk a little about this organism this week.

R. solanacearum can be found not only in the tropics and subtropics, but it is also problematic in temperate areas. This bacterium can cause infection in more than 200 plant species, and loss of plants is estimated to be in the hundreds of millions of dollars every year!! Do you cook with potatoes or tomatoes? Like to plant Geraniums? Or even like bananas? Well, R. solanacearum can infect them all!

This bacterium can be found in the soil, and there just needs to be at least one opening point for R. solanacearum to enter the plant. The bacterium is motile, and can actually sense and move towards the plant itself. A plant wound may be naturally formed as the plant grows, or by animals such as bugs or nematodes, or through every day agricultural activity.

The bacterium colonizes the plant’s internal water system (the xylem), and causes wilting of the leaves. Essentially, as more bacteria start to block parts of the xylem, it disrupts the natural flow of water, and the leaves don’t get all the water they need. If cut, an ooze can be seen leaving the stems, which could lead to bacterial contamination of the soil, and even agricultural equipment. R. solanacearum could also spread through surrounding water, insects, irrigation methods and seeds. If you are a student, can you quickly research which American plant researcher proved that this disease was caused due to bacteria?

So, this particular bacterium is detrimental because it infects so many species of plants in a wide geographical area, is quite lethal, causes great economic loss, and can survive in the environment (under a variety of conditions) for many years. So…what can we do to overcome this problem? Well, it’s always a good idea to use agricultural equipment that are not contaminated. Also, it can help to conduct crop rotation practices, using plants that are resistant to infection, following those that are susceptible. Depending on the extent of the problem, eradication and sanitation efforts may need to take place.

Research has been done on R. solanacearum, but much more is still ongoing to understand the workings of this bacterium that causes this plant wilting away.

Take care until next time! 🙂

Follow the links to read more on R. solanacearum, Geranium, and Erwin Frink Smith. Credit is given for use image of Erwin Frink Smith, wilting in a tomato plant, and brown rot in a potato caused by R. solanacearum.