South Lion Research Articles

Patterns in Age-Seroprevalence Consistent with Acquired Immunity against Trypanosoma brucei in Serengeti Lions

Trypanosomes cause disease in humans and livestock throughout sub-Saharan Africa. Although various species show evidence of clinical tolerance to trypanosomes, until now there has been no evidence of acquired immunity to natural infections. We discovered a distinct peak and decrease in age prevalence of T. brucei s.l. infection in wild African lions that is consistent with being driven by an exposure-dependent increase in cross-immunity following infections with the more genetically diverse species, T. congolense sensu latu. The causative agent of human sleeping sickness, T. brucei rhodesiense, disappears by 6 years of age apparently in response to cross-immunity from other trypanosomes, including the non-pathogenic subspecies, T. brucei brucei. These findings may suggest novel pathways for vaccinations against trypanosomiasis despite the notoriously complex antigenic surface proteins in these parasites.

Dynamics of a multihost pathogen in a carnivore community

1. We provide the first theoretical analysis of multihost disease dynamics to incorporate social behaviour and contrasting rates of within- and between-group disease transmission. 2. A stochastic susceptible-infected-recovered (SIR) model of disease transmission involving one to three sympatric species was built to mimic the 1994 Serengeti canine distemper virus outbreak, which infected a variety of carnivores with widely ranging social structures. The model successfully mimicked the erratic and discontinuous spatial pattern of lion deaths observed in the Serengeti lions under a reasonable range of parameter values, but only when one to two other species repeatedly transmitted the virus to the lion population. 3. The outputs from our model suggest several principles that will apply to most directly transmitted multihost pathogens: (i) differences in social structure can significantly influence the size, velocity and spatial pattern of a multihost epidemic; and (ii) social structures that permit higher intraspecific neighbour-to-neighbour transmission are the most likely to transmit disease to other species; whereas (iii) species with low neighbour-to-neighbour intraspecific transmission suffer the greatest costs from interspecific transmission.

Cross‐disciplinary demands of multihost pathogens

The dynamics of infectious disease spread depend on host population contact structure. Heterogeneities in this contact structure can arise from various forms of demographic and spatial phenomena. Craft et al. (this issue) have constructed an exploratory simulation model of the spread of canine distemper virus through a multispecies carnivore community. Each species in this community is modelled with a contact structure reflecting host social organization, ranging behaviour, and likely interspecific contact patterns. The results are used to infer the possible roles of different species in determining the observed spatio-temporal incidence of canine distemper virus in Serengeti lions during an outbreak in 1993-94.

Climate Extremes Promote Fatal Co-Infections during Canine Distemper Epidemics in African Lions

Extreme climatic conditions may alter historic host-pathogen relationships and synchronize the temporal and spatial convergence of multiple infectious agents, triggering epidemics with far greater mortality than those due to single pathogens. Here we present the first data to clearly illustrate how climate extremes can promote a complex interplay between epidemic and endemic pathogens that are normally tolerated in isolation, but with co-infection, result in catastrophic mortality. A 1994 canine distemper virus (CDV) epidemic in Serengeti lions (Panthera leo) coincided with the death of a third of the population, and a second high-mortality CDV epidemic struck the nearby Ngorongoro Crater lion population in 2001. The extent of adult mortalities was unusual for CDV and prompted an investigation into contributing factors. Serological analyses indicated that at least five “silent” CDV epidemics swept through the same two lion populations between 1976 and 2006 without clinical signs or measurable mortality, indicating that CDV was not necessarily fatal. Clinical and pathology findings suggested that hemoparsitism was a major contributing factor during fatal epidemics. Using quantitative real-time PCR, we measured the magnitude of hemoparasite infections in these populations over 22 years and demonstrated significantly higher levels of Babesia during the 1994 and 2001 epidemics. Babesia levels correlated with mortalities and extent of CDV exposure within prides. The common event preceding the two high mortality CDV outbreaks was extreme drought conditions with wide-spread herbivore die-offs, most notably of Cape buffalo (Syncerus caffer). As a consequence of high tick numbers after the resumption of rains and heavy tick infestations of starving buffalo, the lions were infected by unusually high numbers of Babesia, infections that were magnified by the immunosuppressive effects of coincident CDV, leading to unprecedented mortality. Such mass mortality events may become increasingly common if climate extremes disrupt historic stable relationships between co-existing pathogens and their susceptible hosts.

Ritual vs. retaliatory killing of African lions in the Ngorongoro Conservation Area, Tanzania

The Ngorongoro Conservation Area (NCA), Tanzania, is a multiple land-use area where Maasai pastoralists co-exist with large migratory herbivores and associated carnivores. Maasai retal- iate against lions, leopards and hyenas that prey upon their livestock. Cattle depredation is mostly by lions and most common in grazing herds tended solely by children (rather than by warriors) and in large herds tended by few herders. Depredation on sheep and goats (shoats) is mostly by leopards and is more difficult to prevent. Across all carnivore species, nocturnal depredation is somewhat more common in smaller households. Over most of the NCA, lion killing is proportional to the amount of cattle depredation by resident lions, but nomadic lions from the Serengeti National Park appear to be killed more exclusively for cultural purposes (Ala-mayo) in the open plains. While the impact of ritual hunting on the Serengeti lion population as a whole appears to be trivial, retaliatory killing on resident lions in the NCA may intensify as the human population continues to increase.

Ritual vs. retaliatory killing of African lions in the Ngorongoro Conservation Area, Tanzania

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 6:67-74 (2008) - DOI: https://doi.org/10.3354/esr00120 Ritual vs. retaliatory killing of African lions in the Ngorongoro Conservation Area, Tanzania Dennis Ikanda1, Craig Packer2,* 1Tanzania Wildlife Research Institute, Box 661, Arusha, Tanzania 2Department of Ecology, Evolution & Behavior, University of Minnesota, 1987 Upper Buford Circle, St. Paul, Minnesota 55108, USA *Corresponding author. Email: packer@umn.edu ABSTRACT: The Ngorongoro Conservation Area (NCA), Tanzania, is a multiple land-use area where Maasai pastoralists co-exist with large migratory herbivores and associated carnivores. Maasai retaliate against lions, leopards and hyenas that prey upon their livestock. Cattle depredation is mostly by lions and most common in grazing herds tended solely by children (rather than by warriors) and in large herds tended by few herders. Depredation on sheep and goats (shoats) is mostly by leopards and is more difficult to prevent. Across all carnivore species, nocturnal depredation is somewhat more common in smaller households. Over most of the NCA, lion killing is proportional to the amount of cattle depredation by resident lions, but nomadic lions from the Serengeti National Park appear to be killed more exclusively for cultural purposes (Ala-mayo) in the open plains. While the impact of ritual hunting on the Serengeti lion population as a whole appears to be trivial, retaliatory killing on resident lions in the NCA may intensify as the human population continues to increase. KEY WORDS: Carnivores · Livestock husbandry · Livestock depredation · Ala-mayo · Tanzania Full text in pdf format PreviousNextCite this article as: Ikanda D, Packer C (2008) Ritual vs. retaliatory killing of African lions in the Ngorongoro Conservation Area, Tanzania. Endang Species Res 6:67-74. https://doi.org/10.3354/esr00120 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 6, No. 1. Online publication date: October 14, 2008 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2008 Inter-Research.

Group formation stabilizes predator–prey dynamics

Theoretical ecology is largely founded on the principle of mass action, in which uncoordinated populations of predators and prey move in a random and well-mixed fashion across a featureless landscape. The conceptual core of this body of theory is the functional response, predicting the rate of prey consumption by individual predators as a function of predator and/or prey densities. This assumption is seriously violated in many ecosystems in which predators and/or prey form social groups. Here we develop a new set of group-dependent functional responses to consider the ecological implications of sociality and apply the model to the Serengeti ecosystem. All of the prey species typically captured by Serengeti lions (Panthera leo) are gregarious, exhibiting nonlinear relationships between prey-group density and population density. The observed patterns of group formation profoundly reduce food intake rates below the levels expected under random mixing, having as strong an impact on intake rates as the seasonal migratory behaviour of the herbivores. A dynamical system model parameterized for the Serengeti ecosystem (using wildebeest (Connochaetes taurinus) as a well-studied example) shows that grouping strongly stabilizes interactions between lions and wildebeest. Our results suggest that social groups rather than individuals are the basic building blocks around which predator-prey interactions should be modelled and that group formation may provide the underlying stability of many ecosystems.

The canine distemper epidemic in Serengeti: are lions victims of a new highly virulent canine distemper virus strain, or is pathogen circulation stochasticity to blame?

In the year 1994, the Serengeti lion population was decimated by a canine distemper disease outbreak. Retrospective investigations showed that this host population had already been in contact with the pathogen in 1981 without any detected sign of disease. As an alternative to the virus mutation hypothesis to explain this difference in virulences observed in 1981 and 1994, we propose a novel mechanism of disease emergence based on variation in population immunity. We use a stochastic model to show that stochastic fluctuations in pathogen circulation, owing to a low probability of virus transmission from its reservoir to the target host and thereby resulting in variations in the global immunity level of the target host population, can explain the observations made in Serengeti. This mechanism may also be involved in other infectious disease emergences or re-emergences.

Worldwide occurrence of feline hemoplasma infections in wild felid species.

While hemoplasma infections in domestic cats are well studied, almost no information is available on their occurrence in wild felids. The aims of the present study were to investigate wild felid species as possible reservoirs of feline hemoplasmas and the molecular characterization of the hemoplasma isolates. Blood samples from the following 257 wild felids were analyzed: 35 Iberian lynxes from Spain, 36 Eurasian lynxes from Switzerland, 31 European wildcats from France, 45 lions from Tanzania, and 110 Brazilian wild felids, including 12 wild felid species kept in zoos and one free-ranging ocelot. Using real-time PCR, feline hemoplasmas were detected in samples of the following species: Iberian lynx, Eurasian lynx, European wildcat, lion, puma, oncilla, Geoffroy's cat, margay, and ocelot. "Candidatus Mycoplasma haemominutum" was the most common feline hemoplasma in Iberian lynxes, Eurasian lynxes, Serengeti lions, and Brazilian wild felids, whereas "Candidatus Mycoplasma turicensis" was the most prevalent in European wildcats; hemoplasma coinfections were frequently observed. Hemoplasma infection was associated with species and free-ranging status of the felids in all animals and with feline leukemia virus provirus-positive status in European wildcats. Phylogenetic analyses of the 16S rRNA and the partial RNase P gene revealed that most hemoplasma isolates exhibit high sequence identities to domestic cat-derived isolates, although some isolates form different subclusters within the phylogenetic tree. In conclusion, 9 out of 15 wild felid species from three different continents were found to be infected with feline hemoplasmas. The effect of feline hemoplasma infections on wild felid populations needs to be further investigated.

Planning for success: Serengeti lions seek prey accessibility rather than abundance

Summary We used long‐term radio‐telemetry data to investigate how Serengeti lions (Panthera leo) distribute themselves with respect to hunting opportunities. Specifically, we investigate whether lions hunt in areas where prey are easy to capture or where prey are locally abundant. We used resource‐selection functions (logistic regressions) to measure the location of kills/carcasses with respect to five different habitats: the view‐sheds from large rocky outcrops, river confluences, woodland vegetation, erosion embankments and water sources. As expected for a sit‐and‐wait predator, resting lions spent more time in areas with good cover. On a broad‐scale, lions shifted their ranges according to the seasonal movement of prey, but at a finer scale (< 100 m) lions fed in areas with high prey ‘catchability’ rather than high prey density. Plains lions selected erosion embankments, view‐sheds from rocky outcrops, and access to free water. Woodland lions tended to use erosion embankments, and woody vegetation. The results emphasize the importance of fine‐scale landscape and habitat features when assessing predator–prey theory and conservation.

Tuberculosis in Tanzanian Wildlife

Bovine tuberculosis, caused by Mycobacterium bovis, is a pathogen of growing concern in free-ranging wildlife in Africa, but little is known about the disease in Tanzanian wildlife. Here, we report the infection status of Mycobacterium bovis in a range of wildlife species sampled from protected areas in northern Tanzania. M. bovis was isolated from 11.1% (2/18) migratory wildebeest (Connochaetes taurinus) and 11.1% (1/9) topi (Damaliscus lunatus) sampled systematically in 2000 during a meat cropping program in the Serengeti ecosystem, and from one wildebeest and one lesser kudu (Tragelaphus imberbis) killed by sport hunters adjacent to Tarangire National Park. A tuberculosis antibody enzyme immunoassay (EIA) was used to screen serum samples collected from 184 Serengeti lions (Panthera leo) and 19 lions from Ngorongoro Crater sampled between 1985 and 2000. Samples from 212 ungulates collected throughout the protected area network between 1998 and 2001 also were tested by EIA. Serological assays detected antibodies to M. bovis in 4% of Serengeti lions; one positive lion was sampled in 1984. Antibodies were detected in one of 17 (6%) buffalo (Syncerus caffer) in Tarangire and one of 41 (2%) wildebeest in the Serengeti. This study confirms for the first time the presence of bovine tuberculosis in wildlife of northern Tanzania, but further investigation is required to assess the impact on wildlife populations and the role of different wildlife species in maintenance and transmission.

Ecological Change, Group Territoriality, and Population Dynamics in Serengeti Lions

Territorial behavior is expected to buffer populations against short-term environmental perturbations, but we have found that group living in African lions causes a complex response to long-term ecological change. Despite numerous gradual changes in prey availability and vegetative cover, regional populations of Serengeti lions remained stable for 10- to 20-year periods and only shifted to new equilibria in sudden leaps. Although gradually improving environmental conditions provided sufficient resources to permit the subdivision of preexisting territories, regional lion populations did not expand until short-term conditions supplied enough prey to generate large cohorts of surviving young. The results of a simulation model show that the observed pattern of "saltatory equilibria" results from the lions' grouping behavior.

Serological and demographic evidence for domestic dogs as a source of canine distemper virus infection for Serengeti wildlife

Following an epidemic of canine distemper virus (CDV) in Serengeti lions in 1994, the role of domestic dogs in the epidemiology of the disease was investigated by serological and demographic analyses. From 1992 to 1994, data were collected from two domestic dog populations bordering the Serengeti National Park. Several lines of evidence indicated that patterns of CDV infection differed significantly between higher-density dog populations of Serengeti District to the west of the park and lower-density populations of Ngorongoro District to the south-east: (a) CDV age-seroprevalence patterns differed significantly between years in Ngorongoro District populations but not in Serengeti District populations; (b) CDV seropositive pups (<12 months of age) were detected in Ngorongoro District only in 1994, whereas a proportion of pups in Serengeti District were seropositive in each year of the study; (c) in Ngorongoro District, the proportion of deaths attributed to disease was significantly higher in 1994 than in 1993, whereas in Serengeti District, there was no significant difference in disease-related mortality between years; (d) in Ngorongoro District, significantly more CDV seronegative dogs than seropositive dogs died in 1994, whereas there was no difference in survival of CDV seropositives and seronegatives between years in Serengeti District. We concluded that, between 1992 and 1994, CDV persisted in higher-density dog populations of Serengeti District, but occurred only sporadically in lower-density Ngorongoro District populations. Data from Ngorongoro District are consistent with exposure of dogs to CDV in 1991 and 1994, but not in 1992 and 1993. These findings suggest that higher-density domestic dog populations to the west of the Serengeti National Park were a more likely source of CDV infection for wildlife during 1994 than lower-density pastoralist dogs to the south and east of the park.

Genetic characterization of canine distemper virus in Serengeti carnivores

The lion ( Panthera leo) population in the Serengeti ecosystem was recently afflicted by a fatal epidemic involving neurological disease, encephalitis and pneumonia. The cause was identified as canine distemper virus (CDV). Several other species in the Serengeti were also affected. This report presents CDV H and P gene sequences isolated from Serengeti lions ( Panthera leo), spotted hyenas ( Crocuta crocuta), bat-eared fox ( Otocyon megalotis) and domestic dog ( Canis familiaris). Sequence analyses demonstrated that the four Serengeti species carry closely related CDV isolates which are genetically distinct from other CDV isolates from various species and locations. The results are consistent with the conclusions that: (1) a particularly virulent strain of CDV emerged among Serengeti carnivores within the last few years; (2) that strain has recognizable shared-derived (synapomorphic) genetic differences in both H and P genes when compared to CDV from other parts of the world; and (3) that the CDV strain has frequently crossed host species among Serengeti carnivores.

Wakley Prize, 1997

Last year Imre Loefler, winner of The Lancet's first Wakley Prize, wrote from Nairobi, Kenya, about his Aunt Teresa's pekinese (whose balanitis was treated with topical Prontosil), Serengeti lions, and what his mother might have thought about the Pope. His point about strategies against infection was vividly made: “Our folly ultimately was not just due to carelessness and avarice; the concept was wrong. We, the healers, went to war against countless unwanted species and the war was a total one, aiming at annihilation and extinction. Our terminology in the process was that of the warrior: we were fighting, conquering, eliminating, exterminating, and, as in all wars with infinite aims, the damage incurred is inestimable.”

Correction: A canine distemper virus epidemic in Serengeti lions (Panthera leo)

Nature 379, 441–445 (1996). IN this Letter, we neglected to refer to the paper by T. C. Harder et al (Vaccine 13, 521-523; 1995) which reported canine distemper virus P gene sequences from two Serengeti lions that were victims of the same epidemic as those that were the subject of our Letter. MJ.G.A. and M.

A canine distemper virus epidemic in Serengeti lions (Panthera leo).

CANINE distemper virus (CDV) is thought to have caused several fatal epidemics in canids within the Serengeti–Mara ecosystem of East Africa, affecting silver-backed jackals (Canis mesomelas) and bat-eared foxes (Otocyon megalotis) in 1978 (ref. 1), and African wild dogs (Lycaon pictus) in 1991 (refs 2, 3). The large, closely monitored Serengeti lion population4,5 was not affected in these epidemics. However, an epidemic caused by a morbillivirus closely related to CDV emerged abruptly in the lion population of the Serengeti National Park, Tanzania, in early 1994, resulting in fatal neurological disease characterized by grand mal seizures and myoclonus; the lions that died had encephalitis and pneumonia. Here we report the identification of CDV from these lions, and the close phylogenetic relationship between CDV isolates from lions and domestic dogs. By August 1994, 85% of the Serengeti lion population had anti-CDV antibodies, and the epidemic spread north to lions in the Maasai Mara National reserve, Kenya, and uncounted hyaenas, bat-eared foxes, and leopards were also affected.

Phylogenetic evidence of canine distemper virus in Serengeti's lions

Recently an epizootic, reported to be due to a morbillivirus infection, affected the lion population of the Tanzanian Serengeti National Park. A morbillivirus phosphoprotein (P) gene fragment was amplified by PCR from tissue samples of several affected lions. Sequencing of the amplificates and subsequent phylogenetic analyses revealed that a wild-type strain of canine distemper morbillivirus (CDV) was involved. Vaccination of the local domestic dog population with proven safe CDV vaccines is proposed.

A lion lentivirus related to feline immunodeficiency virus: epidemiologic and phylogenetic aspects

Feline immunodeficiency virus (FIV) is a novel lentivirus that is genetically homologous and functionally analogous to the human AIDS viruses, human immunodeficiency virus types 1 and 2. FIV causes immunosuppression in domestic cats by destroying the CD4 T-lymphocyte subsets in infected hosts. A serological survey of over 400 free-ranging African and Asian lions (Panthera leo) for antibodies to FIV revealed endemic lentivirus prevalence with an incidence of seropositivity as high as 90%. A lion lentivirus (FIV-Ple) was isolated by infection of lion lymphocytes in vitro. Seroconversion was documented in two Serengeti lions, and discordance of mother-cub serological status argues against maternal transmission (in favor of horizontal spread) as a major route of infection among lions. A phylogenetic analysis of cloned FIV-Ple pol gene sequences from 27 lions from four African populations (from the Serengeti reserve, Ngorongoro Crater, Lake Manyara, and Kruger Park) revealed remarkably high intra- and interindividual genetic diversity at the sequence level. Three FIV-Ple phylogenetic clusters or clades were resolved with phenetic, parsimony, and likelihood analytical procedures. The three clades, which occurred not only together in the same population but throughout Africa, were as divergent from each other as were homologous pol sequences of lentivirus isolated from distinct feline species, i.e., puma and domestic cat. The FIV-Ple clades, however, were more closely related to each other than to other feline lentiviruses (monophyletic for lion species), suggesting that the ancestors of FIV-Ple evolved in allopatric (geographically isolated) lion populations that converged recently. To date, there is no clear evidence of FIV-Ple-associated pathology, raising the possibility of a historic genetic accommodation of the lion lentivirus and its host leading to a coevolved host-parasite symbiosis (or commensalism) in the population similar to that hypothesized for endemic simian immunodeficiency virus without pathology in free-ranging African monkey species.

The barefoot expert: the interface of computerized knowledge systems and indigenous knowledge systems

From the Publisher: It may seem a strange match--AI and crop irrigation or AI and the Serengeti lions but researchers in Artifical Intelligence envision expert systems as a new technology for capturing the knowledge and reasoning process of experts in agriculture, wildlife management, and many other fields. These computer programs have a relevance for developing nations that desire to close the gap between themselves and the richer nations of the world. Despite the value and appeal of expert systems for economic and technological development, Schoenhoff discloses how this technology reflects the Western preoccupation with literacy and rationality. When expert systems are introduced into developing nations, they must interact with persons who reason and articulate their knowledge in ways unfamiliar to high-tech cultures. Knowledge, particularly in poor and and traditional communities, may be expressed in proverbs rather than propositions or in folklore rather than formulas. Drawing upon diverse disicplines, the author explores whether such indigenous knowledge can be incorporated into the formal language and artificial rationality of the computer-and the imperative for working toward this incorporation.