Complex sentence: The 2004 Locust Swarm was the largest infestation of desert locust in West and North Africa in more than 15 years and impacted a number of countries in the fertile northern regions of Africa.
Split into simpler sentences: The 2004 Locust Swarm is the largest infestation of desert locust that has happened in West and North Africa in more than 15 years. The plague has had an effect on a large number of countries in the fertile northern regions of Africa.