World’s tiniest library could be key to saving millions of cattle

One of the world’s smallest and strangest bacteria also is responsible for one of the most devastating cattle diseases.

The tiny bacteria, Mycoplasma mycoides subspecies mycoides (Mmm), cause contagious bovine pleuropneumonia (CBPP) when inhaled by cattle.

CBPP is a huge barrier to cattle farming in sub-Saharan Africa, where it is endemic in at least 12 countries. It is estimated to cost the continent over 38.8 million United States dollars a year.

To fully understand these deadly bacteria, and pave the way to developing a better vaccine, scientists at the International Livestock Research Institute (ILRI) are constructing a full library of their genes and their possible functions.

Cattle with CBPP develop painful and inflamed, fluid-filled lungs, causing difficulty breathing and coughing.

CBPP can infect nearly all of a herd and kill up to 50% of animals. Those that survive become weakened, and some may become chronic carriers that will breathe the bacteria onto other naive cattle.

Disease symptoms may appear several days to months following infection, so traditional methods of pastoralism and moving cattle over long distances can contribute to its spread.

Although a vaccine is available, it has limited efficacy, and sometimes causes severe side effects which can make pastoralists reluctant to use it.

Mmm are part of a class of bacteria called mollicutes. In addition to lacking a cell wall—usually a widespread feature of bacteria—mollicutes have especially small genomes, by bacterial standards.

This is why scientists once chose a member of the Mycoplasma bacteria family to be assembled from components in 2008, as the world’s very first ‘synthetic organism’.

A tiny genome still hides an immense complexity. But it also opens up possibilities for a notable research approach currently being conducted at ILRI.

Photo: Cattle in Isiolo County, Kenya (photo credit: ILRI/Geoffrey Njenga)