Political tension in Nigeria and the devaluation of the local currency hit first half profit of soap maker PZ Cussons.The company, which produces Imperial Leather soaps, said in the six months to 30 November profit fell 8.2% from the corresponding period a year ago, while revenue declined 10% to £386.7m.The group cited "challenging trading conditions" in Nigeria, its biggest market, as the main factor behind the slump in profit and revenue, as distributors and customers in the African country have become more cautious."There are few indications of a short-term improvement in the environment, with potentially some further disruption around the forthcoming presidential elections," Investec Securities analyst Nicola Mallard said in a note on Tuesday.Profit before tax and exceptional items fell from £47.6m to £43.7m, while revenue from Africa, which constitutes 42% of the group's total revenue, fell 6% to £156.2m.However, the soap maker raised its interim dividend to 2.61 pence from 2.53 pence a year earlier.PZ shares were up 2.22% to 317.90p at 15:17 on Tuesday.