Acta Tropica 96 (2005) 24–30 The impact of development and malaria control activities on its vectors in the Kinabatangan area of Sabah, East Malaysia I. Vythilingam a,∗ , S.T. Chan a , C. Shanmugratnam b , H. Tanrang b , K.H. Chooi c a Infectious Diseases Research Centre, Institute for Medical Research, Jalan Pahang, 50588 Kuala Lumpur, Malaysia b Vector Borne Disease Control Programme, Kota Kinabalu, Sabah, Malaysia c Vector Borne Disease Control Programme, Shah Alam, Selangor, Malaysia Received 28 June 2004; received in revised form 5 April 2005; accepted 28 June 2005 Available online 1 August 2005 Abstract A study was carried out from July 2001 until January 2003 in the Kinabatangan area of Sabah, part of Borneo island, where malaria used to be mesoendemic. Vector surveys determined that Plasmodium falciparum was the predominant species and Anopheles balabacensis the primary vector. Malaria cases have dropped drastically over the years but P. falciparum is still predominant. In the present study, Anopheles donaldi was the predominant species and was positive for sporozoites. Although An. balabacensis was present, none were infective. An. donaldi bite more outdoors than indoors and have a peak biting time from 18:00 to 19:00 h when most people are still out of their homes. An integrated malaria control programme along with area development has helped in the control of malaria and its vector. © 2005 Elsevier B.V. All rights reserved. Keywords: Malaria; Sporozoites; Peak biting time 1. Introduction Malaria is a serious public health problem in many countries in South East Asia, with Sabah being one of the more affected regions in recent history. The State of Sabah covers an area of 76,114.92 km 2 and is situated on the northern part of the island of Borneo. Malaria cases in the early 1990s were around 50,000, with the ∗ Corresponding author. Tel.: +60 340402437; fax: +60 326948724. E-mail address: indra@imr.gov.my (I. Vythilingam). past 3 years seeing a steady decline to 6050, 5096 and 1770 for years 2001, 2002 and 2003, respectively (VBDCP Sabah). There is a history of well organised antimalarial operations and entomological surveys in Sabah dating back to1914 (Hii, 1985a). In the 1950s, Anopheles balabacensis Baisas was recognised as the most dangerous vector in Sabah (McArthur, 1950; Colless, 1952). Colless (1952) deter- mined that a strong correlation existed between the adult density and the sporozoite rate in An. balabacen- sis and that adult longevity correlated well with climatic conditions. In 1955, a malaria pilot project was initiated 0001-706X/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.actatropica.2005.06.022