Zoonotic diseases constitute a large percentage of the infectious diseases ravaging the country. Experts estimate that 60 per cent of existing human infectious diseases come from animals.
The diseases, which are transferred from animals to humans, leave in their wake, illness, deaths and disabilities, with some of them occurring perennially as epidemics every year over the last five decades.
Aside the recurring ones, the country has also recorded some zoonotic disease outbreaks that were imported from other countries like the Ebola virus disease (EVD) importation into the country in 2014.
The Nigeria Centre for Disease Control and Prevention (NCDC), last month said Nigeria was at a high risk of importation of the Ebola virus disease in Uganda.
Experts say there is need to prioritise and strengthen preparedness and response to zoonotic diseases. While some of the diseases can be prevented through vaccination, access to timely vaccination is sometimes a challenge.
The NCDC said zoonotic diseases were gotten from animals through the environment or direct contact.
It said zoonotic diseases repeatedly posed threats to humans and animals with significant disability and death rates.
Dr Muhammad Shakir Balogun, a Medical Microbiologist and Epidemiologist at the African Field Epidemiology Network (AFENET), said a whopping 75 per cent of emerging diseases were also zoonotic, and that out of the five new diseases that emerge every year, three were zoonotic in origin.
He said Nigeria had a high burden of zoonotic diseases, adding that many zoonotic diseases are associated with underdevelopment and poverty. The vast majority of bioterrorism pathogens are also zoonotic, he added.
He said, “Zoonoses represent a major public health problem, not just in Nigeria, but around the world due to our close relationship with animals in agriculture as livestock or draught animals, as companion animals and in the natural environment. Many of these zoonoses don’t receive enough attention, and are, therefor known as the neglected zoonoses.
“Zoonoses such as avian influenza can also cause disruptions in the production and trade of animal products for food and other uses.”
Dr Balogun, who is also the Resident Advisor, Nigeria Field Epidemiology and Laboratory Training Programme, said zoonotic infections that are endemic in Nigeria include COVID-19, monkey pox, tuberculosis, trypanosomiasis, toxoplasmosis, taeniasis (tape worm infestation), rabies, brucellosis, Lassa fever and yellow fever. Yellow fever and tuberculosis have vaccines that can be used for their prevention, he said.
Dr Mohammed Abbas of the Department of Medical Microbiology and Parasitology, Bayero University, Kano said it was worrisome that 60 per cent of infectious diseases came from zoonotic sources.
He said, “This calls for urgent attention by the federal government to ensure the availability of coordinated surveillance systems in the animal and public health sectors for zoonotic diseases/pathogens.”
Burden of some of the zoonotic diseases in Nigeria
Lassa fever remains a major public health challenge in West Africa, with Nigeria bearing a high burden.
It is a viral hemorrhagic illness caused by contact with food or household items contaminated with rodent urine or faeces.
The virus is carried in multimammate rats, the common soft-furred African rat whose female has a double row of breasts.
Nigeria has been recording persistent seasonal outbreaks of Lassa fever, 52 years after it was discovered in the country.
Data from the NCDC shows that this year alone, 178 deaths, 7,492 suspected cases and 989 confirmed cases have so far been recorded from Lassa fever from 26 states and 106 local government areas. Of all confirmed cases, 71 per cent are from Ondo (33%), Edo (25%) and Bauchi (13%) states.
There were also 55 confirmed cases among health workers since the beginning of this year.
Last year, 89 deaths, 3,567 suspected cases, 410 confirmed cases were recorded from 15 states and 61 local government areas.
Rabies claims about 55, 000 lives every year, with rabid dogs accounting for about 94 per cent of confirmed human infection, the World Health Organisation (WHO) stated.
The WHO Nigeria country representative, Dr Walter Kazadi Mulombo, said rabies infection was caused by a virus which is often transmitted to humans through the bites of infected animals, especially dogs.
Represented by the Deputy Country Representative, Alexander Chimbaru, at an event, he said there had been recent reported cases in Gombe and Enugu states.
While saying that school children and women were frequent victims, he said most cases resulted in deaths and there is an urgent need to address it.
Monkeypox is a rare viral disease transmitted from animals to humans and from humans to humans.
Animal-to-human transmission may occur by direct contact with blood, body fluids, skin or mucosal lesions of infected animals, example, monkeys, squirrels and rodents. The symptoms include fever, body pain, weakness, sore throat and rashes on the face, palms, soles of the feet and other parts of the body.
Several countries worldwide have also been affected by an unprecedented outbreak of monkeypox this year.
The Director-General of the World Health Organisation (WHO), Dr Tedros Adhanom Gebreyesus, had declared monkeypox a public health emergency of international concern .
Since the re-emergence of monkeypox in Nigeria in September 2017, the country has continued to record sporadic cases of the disease from states across the country, especially from the South South part of Nigeria.
Until the outbreak of 2017, the last time cases of monkeypox were reported in Nigeria was in the 1970s.
A total of 1,549 suspected cases, 604 confirmed cases and seven deaths have been recorded from January 1 to October 30, 2022 from 31 states and the Federal Capital Territory (FCT).
The grand total of 830 confirmed cases have been recorded from September 2017 to October 30 this year.
An analysis of the NCDC situation reports on monkeypox showed that the number of confirmed cases recorded between January and August this year is higher than each of the total cases recorded in 2017, 2018, 2019, 2020 and 2021.
The NCDC said there were no specific treatments available for monkeypox infection, though various novel antivirals have in-vitro and animal data supportive of effect such as Brincindofovir and Tecovirimat.
“Vaccination against smallpox has been proven to be 85 per cent effective in preventing monkeypox but is no longer routinely available following global smallpox eradication. Post-exposure vaccination may help prevent the disease or reduce its severity,” it stated.
Dr Stephanie Oni-Ogunbor said the impact of monkey pox on the health and the economy was enormous, adding that increased sensitisation about the disease amongst the populace would go a long way in preventing the disease.
Cholera is a disease of the intestinal system caused by a bacteria called vibrio cholera. It is usually transmitted through the faeco oral route which means ‘from faeces to mouth’ or from hands contaminated with the bacteria put in the mouth.
As at October 2, 2022, a total of 10,745 suspected cases, including 256 deaths (CFR2.4%) have been reported from the 31 states this year, according to NCDC data.
Measles, COVID-19, yellow fever
Measles is one of the leading causes of deaths and disability among children under five years, and if not well managed, could lead to deafness, mental retardation, convulsion, and vulnerability to other diseases.
Borno (166), Jigawa (94), Katsina (88), Kebbi (70), Kwara (43) and Anambra (40) accounted for 55.2 per cent of the 908 suspected cases reported in January this year.
Of the 908 suspected cases reported, 254 (28.0%) were confirmed. A total of 54 local government areas across 16 states reported at least one confirmed case.
From January to December, 2021, 15,792 suspected cases were reported. Of the suspected cases reported, 10,096 (63.9%) were confirmed. A total of 109 deaths were recorded among confirmed cases.
The novel coronavirus was discovered, causing illness at the Wuhan wet market China in late 2019.
Nigeria recorded her first COVID-19 case on February 27, 2020. Since the first case of COVID-19 in Nigeria, the country has witnessed waves of the pandemic with spike in cases, as well as decreased daily infections in between in the last two years.
Since the index case, the number of confirmed cases in the country has grown to 266, 283 cases. Out of the number, 259,643 cases have been discharged and 3,155 deaths recorded in 36 states and the FCT.
The director-general of the NCDC, Dr Ifedayo Adetifa, at a news briefing, said the impacts of COVID-19 continued to be felt across several other areas, including the increase in the risk of measles and probable increase in yellow fever outbreaks due to delayed planned vaccination campaigns.
Why does Nigeria perennially experience zoonotic diseases?
Dr Balogun said poverty, poor sanitation, poor health education, poorly implemented prevention and control strategies, unsafe animal husbandry practices, poor immunisation uptake for vaccine preventable diseases.
He said factors that have been increasing Nigeria’s risk of zoonotic diseases are increasing population, which makes human encroach into spaces inhabited by wildlife; climate change; weak health system; inappropriate technology in industry and agriculture; change in animal populations; antimicrobial resistance.
Impact on health, economy and development of the country
The epidemiologist, Dr Balogun said some zoonoses like Lassa fever tend to occur as epidemics leading to the disruption of routine health care delivery and further worsening existing health problems
He, however, said, ”We don’t have the exact burden of zoonotic diseases in Nigeria because surveillance is not adequate. Many of them are so neglected that we don’t have accurate data on them.”
“Health is wealth. Apart from the loss in productivity directly due to the illnesses caused by zoonotic infections, there are other effects on the economy. Zoonotic infections also cause illness in animals, leading to loss of commercial livestock and a threat to food security and even loss of livelihood of farmers. They can lead to disruptions in trade with other countries.”
Ajuma, a resident of Kogi State, who lost three relatives to Lassa fever, told our reporter that she wants increased efforts in tackling zoonotic diseases, particularly Lassa fever.
“There should be increased sensitisation of the public; and government should put measures in place to prevent them,” she said.
What is the way out, especially in the area of prevention, preparedness and response?
Prevention methods for zoonotic diseases differ for each pathogen, according to Dr Balogun. However, he said several practices were recognised as effective in reducing risk at the community and personal levels.
He said One Health strategy should be fully adopted and implemented, safe and appropriate guidelines for animal care in the agricultural sector help to reduce the potential for food-borne zoonotic disease outbreaks (e.g, salmonellosis) through foods such as meat, eggs, dairy or even some vegetables.
Standards for clean drinking water and waste removal, as well as protection for surface water in the natural environment, are also important and effective.
Health education campaigns to promote hand washing after contact with animals and other behavioural adjustments can reduce community spread of zoonotic diseases when they occur. Research into diagnostics, treatment and vaccines should be strengthened.
Professor Junaidu Usman Abdullahi of Veterinary Public Health and Commissioner for Agriculture in Sokoto State advocated the establishment of zoonotic units at federal teaching hospitals in the country. He said doing so was important to bridge the gap.
“From my experience, I realised a gap in the depth of knowledge when it comes to zoonotic diseases. I say this because I have been teaching medical students at master’s level and I know that the knowledge is not commensurate with the requisite strategy when it comes to zoonotic disease aspects. So I believe the federal government can do more of this,” he said.
The national president of the National Association of Government General Medical and Dental Practitioners (NAGGMDP), Dr Noel Dokun, said there was need for the federal government to adopt homegrown solutions in tackling brain drain, monkey pox and other epidemics, as well as other challenges bedeviling the health sector of the country.
He also called for a preventive approach in tackling diseases instead of the curative one being utilised in the country.
Importance of one health approach/strategy
The One Health approach is crucial to the prevention and control of zoonotic diseases in the country Dr Balogun said, adding that a multidisciplinary approach involving experts in human medicine and public health, veterinarians and environmental scientists is necessary.
He said , “There’s a One Health TWG coordinated by the NCDC. The NCDC has worked with other MDAs and partners to develop a One Health Strategy and Implementation Plan that is not fully funded.”
He said strengthening the One Health approach is one of the strategic priorities of the African Field Epidemiologic Network (AFENET), and it has been working to support the development of the One Health approach in Nigeria.
Presenting the National Strategic Plan for Elimination of Dog-Mediated Human Rabies in Nigeria, Prof Junaidu Kabir, the Dean of Veterinary Medicine, Ahmadu Bello University, Zaria said vaccinating 70 per cent of the population against rabies would enable the country save revenue annually.
He said N31.5billion was required to implement the plan over the next five years.
The NCDC did not respond to questions on what it is doing to strengthen preparedness and response to zoonotic diseases at press time. However, on its Twitter handle, it stated that prevention and control of zoonotic diseases required the collective effort of human, animal and environmental sectors.
“These diseases are called zoonotic diseases and need to be tackled using a One Health approach,” it stated.
The NCDC stated that in collaboration with other ministries, departments and agencies, it had developed a five-year strategic plan (2019-2023), with a one-year implementation plan for One Health in Nigeria.