…as public health expert enumerates measures to combat outbreak
The Nigeria Center for Disease Control has revealed that the country recorded about 2,115 cases of Lassa fever in the past seven months.
The NCDC said that the number of the reported cases of the deadly disease had risen grossly in the country between January and July.
In a situation report provided by the center at the end of the 27th week of the year, the NCDC said that the cases were recorded in 21 different states in the country, making a cumulative number of 2115 cases.
The agency, in a statement issued as a weekly situation report, signed by its Chief Executive Officer, Dr. Chikwe Ihekweazu, noted that patients in the 21 states were currently being followed up to prevent further infection.
The NCDC also said that the Lassa fever national multi-partner and multi-agency Technical Working Group would continue to coordinate response activities at all levels.
The agency said, “From 1st January to July 2018, a total of 2,115 suspected cases had been reported from 21 states. Of these, 446 were confirmed positive, 10 are probable, 1652 negative. Since the onset of the 2018 outbreak, there have been 115 deaths in confirmed cases and 10 in probable cases. Case Fatality Rate in confirmed cases is 25.4 per cent.”
“Twenty-one states have recorded at least one confirmed case across 71 Local Government Areas (Edo, Ondo, Bauchi, Nasarawa, Ebonyi, Anambra, Benue, Kogi, Imo, Plateau, Lagos, Taraba, Delta, Osun, Rivers, FCT, Gombe, Ekiti, Kaduna, Abia and Adamawa). Seventeen states have exited the active phase of the outbreak while four – Edo, Ondo, Plateau and Taraba states – remain active.”
The NCDC also stated the level of follow-up given to these states.
“A total of 5713 contacts have been identified from 21 states. Of these, 156(2.7 per cent) are currently being followed up, 5547 (97.1 per cent) have completed 21 days follow-up while 10 (0.2 per cent) were lost follow-up. Eighty-five symptomatic contacts have been identified; of which 29 (34 per cent) have tested positive from five states (Edo -13, Ondo – 8, Ebonyi – 3, Kogi – 3 Bauchi -1 and Adamawa -1),” the centre said.
Meanwhile, when asked if eradicating rats would check the outbreak of the deadly disease, a public health expert, Dr. Simbo Davidson, said that not all rats carried the
virus.
Davidson said, rather, a particular specie of mouse could spread the virus.
The public health expert further explained measures that could be used to combat the outbreak and spread of the disease, saying, “It is true that Lassa fever is spread by mice, and it is also a good idea to decrease rat and mice population through effective pest control. However, not all species of mice harbour the Lassa fever virus. Then, the specific reservoir for the Lassa fever virus is a mouse called Mastomys natalensis and not a rat. Furthermore, Mastomys natalensis have been found to infest homes in both rural and urban areas.
“In rural areas, these mice could very well be hiding out in forest regions, rather than in homes. So, rodent control measures need to factor this in. Nevertheless, several studies, including a study by Safronetz et al (2013) have uncovered the fact that only 20-30 per cent of Mastomys natalensis mice actually have the Lassa fever virus in their blood streams, and many rat species do not usually have the virus. So, this really means that if you eliminate 100 rodents of Rattus rattus specie from target homes in a community, you may be decreasing the risk of Lassa fever epidemics by exactly zero per cent, but you may have reduced the risk of other rodent-related illnesses by 50 per cent.
“What this tells us is that zoologists will need to map the country by trapping and testing samples of rats and mice, in order to more accurately determine the specific high risk Lassa fever areas where infected Mastomys rats thrive. This is what other countries have done. Hence, in such identified areas, environmental and infrastructural controls have been introduced, because nationwide rodent elimination methods are not really considered practical or feasible (considering the toxicity of pesticides and rodenticides in food and water).”