Bovine Tuberculosis (bTB):
Mycobacterium bovis, the causative agent of bovine tuberculosis (bTB) was introduced in the southern part of Kruger National Park by domestic cattle. The disease has spread northwards through infected African buffalos (Syncerus caffer) with serious concerns for the viability of the Kruger lion population as well as the development of the Greater Limpopo Trans-frontier Conservation area . Aside from the clinical effects of bTB leading to greater mortality in affected populations the prevalence of the disease within Kruger has also been shown to drive social change with lower lion survival and breeding success with more frequent male coalition turnover and consequent higher infanticide.
Elsewhere, among the Serengeti lions, 4% of animals tested were seropositive for bTB . The disease is also present in reserves adjacent to Kruger NP including Hluhuwe-iMfolozi . bTB also occurs among buffalos in Queen Elizabeth NP, Uganda, although so far not observed among resident lions , and also among lechwe (Kobus leche) in Zambia’s Kafue NP . Lions in Mozambique’s Niassa reserve have tested negative for the disease (Colleen Begg, pers comms. 2011)
Canine Distemper (CDV):
Canine Distemper Virus (CDV) affects both free-living and captive carnivores worldwide, and is now recognised as a cause of large-scale epidemics in felids ]. Primarily transmission is by aerosol transfer or contact with bodily exudates containing the virus. Clinical symptoms mainly affect the respiratory, gastro-intestinal and central nervous systems, causing grand mal seizures and myoclonus with mortalities usually occurring due to encephalitis or pneumonia.
Lion populations in the Serengeti-Mara ecosystem experienced two major CDV epidemics in 1994 and 2001, with the disease originating in domestic dogs. The 2001 outbreak in the Ngorongoro Crater caused 35% mortality among its small population of lions , while the 1994 outbreak that hit the Serengeti National Park lions, spreading North to Kenya’s Maasai Mara National Reserve infected 85% of lions causing mortalities in a third of the 3000 strong population . Several other carnivore species were also affected and a single CDV variant was found circulating in lions, spotted hyenas, bat-eared foxes, and domestic dogs, suggesting extensive inter-specific transmission.
Possible explanations for such high mortality rates of infection in these outbreaks include the emergence of a particularly virulent strain of CDV, repeated introduction due to multi-host disease spill-over and climate extremes, coinciding with both outbreaks, which created conditions exacerbating the immunosuppressive effects of infection, which may otherwise have been tolerated in isolation .
CDV antibodies have also been detected in Central Kalahari lions and in Uganda’s Queen Elizabeth National Park . CDV has been, and continues to be, present across much of Southern Africa, in its domestic dog and wild carnivore populations. Lions in Mozambique’s Niassa reserve have tested negative for the disease (Colleen Begg, pers comms.
Feline Parvovirus (FPV):
Also known as feline infectious enteritis (FIE) or feline panleukopenia, feline parvovirus (FPV) is an acute, enteric, viral infection of domestic and exotic felines caused by a single stranded DNA virus, from the Parvoviridae family
Parvovirus is very stable in the environment and indirect transmission can spread rapidly. In naïve populations this can be the cause of high mortality.
Clinical symptoms include depression, vomiting and diarrhoea. Ataxia (tremors and jerky movements) may also ensue due to cerebellar hypoplasia which will be more noticeable in young cubs .
Antibody titers for FPV are highly prevalent in Serengeti populations (75%) but less so in the nearby Ngorongoro Crater population (27%). Other locations with published results include Laka Manyara region (60%), Kruger National Park (84%), Etosha National Park (0%) and Central Kalahari Game Reserves (0%) .
Feline Calicivirus (FCV):
Feline Calicivirus (FCV) has been well documented among domestic felines; more so than exotic felids. Nevertheless, this highly prevalent pathogen has been found to have infected wild members of the Felidae , and the nature, severity and clinical signs associated with FCV in exotic felines are similar to those reported in domestic cats .
FCV is related to upper respiratory tract diseases and can be identified by rhinitis, pneumonia, fever, lameness and oral ulcerations . The FCV strain usually causes temporary infection and appears to be harmless in most cases. However, upon recovery, the infected host may still act as an asymptomatic carrier ; potentially infecting those who are susceptible to the disease.
Outbreaks of the virus have been reported in different lion populations residing in Africa. The prevalence rate has fluctuated in each population, with FCV being absent from the small, isolated Crater population in Ngorongoro , to occurring at low prevalence in Botswana , to being highly prevalent in the Serengeti Plains . This suggests that the FCV infection occurs in populations of high density, with outbreaks increasing as the size of the susceptible host population grows .
Feline Coronavirus (FCoV) :
Feline Coronavirus is an upper respiratory infection not dissimilar to FHV, which is transmitted by various routes; faecal, oral and possibly aerosolized. It can infect domestic animals such as dogs and in cats has been known to develop into the more pathogenic feline infectious peritonitis . It has also been found to be the cause of high mortality in domestic kittens.
Like many of the other epidemic diseases (such as parvovirus or calicivirus) found in serological studies of lions there have been no consistent signs of clinical disease for FCoV .
Unlike the endemic diseases, FCoV is an epidemic disease, and thus has different implications for wild lion populations. Epidemic diseases by nature briefly sweep through a population often inflicting a high mortality rate however, due to this high mortality and a lack of further susceptible hosts the initial bursts are short lived. The disease will then return through the population at a later date once there are sufficient numbers of susceptible individuals, known cases of this include coronavirus, parvovirus and calicivirus in the Serengeti lion population . FCoV has been found in varying levels of population infection throughout African lion populations .
Feline Infectious Peritonitis (FIP)
Feline Infectious Peritonitis is a viral disease caused by some strains of feline coronavirus (FCoV) either by mutation of the virus or by an aberration of the immune response. Cats with weak immune systems such as young or old cats and those infected with feline leukaemia virus (FeLV) are at particular risk from developing FIP from FCoV.
An intense inflammatory reaction occurs around vessels in the tissue; often in the abdomen, kidney or brain. The virus is unique in that antibodies actually assist the infection of white blood cells of the FIP virus. Clinical FIP is progressive and almost always fatal. Symptoms include inappetance, weight loss, depression, anemia, fever and roughening of the fur. Fluid may also accumulate in the abdomen causing difficulty in breathing when accumulation becomes significant.
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