Disease detectives track buffalo in Ruaha National Park

We received a great update from HALI's own Dr. Annette Roug last week, who has been in Tanzania with our team and the Tanzania National Park vets continuing their ongoing study of park buffalo populations....

- Annette Roug

During the last few weeks, HALI team members were back in Ruaha National Park for buffalo work. The GPS collars that we placed in 2014 have now run out of battery.  We attempted to find buffaloes with collars in order to remove the collars. In addition, we sampled another five animals for disease testing and conducted demographic surveys. 

The capture and sampling of the five additional animals were successful. We sampled four bulls and one cow from three different herds. We succeeded in removing one collar. The cow had a little calf and both looked very healthy. 

The pictures show the sampling of buffalo bulls near Jongomero, and one shows HALI's Erasto Katowo and myself removing the collar from the cow with the ID SAT1497. The remaining are photos of buffalo and the blood tubes that we collect.

Three Days Among Ruaha's Buffalo Herds in the Wet Season

 In October 2014, HALI and Ruaha National Park researchers sampled and placed satellite GPS collars on 10 adult female buffaloes in order to learn more about the health and herd movements of the Ruaha buffalo population.

Below you’ll find three days of dispatches from the most recent buffalo survey work. For a basic overview of the project, listen to this interview with David Wolking. Annette Roug is leading the HALI buffalo research in the park.

The goal of the wet-season buffalo survey was to determine herd sizes, locate collared buffaloes, and if possible, assess herd composition. We also wanted to record habitat types in areas most frequently used by the buffaloes during the wet season.
 
Day 1, February 25
Ruaha National Park graciously provided a plane that enabled us to conduct an initial survey from the air. We saw and photographed all but one of the buffalo herds with collared animals from the plane. Four animals were located north of Jongomero, one between Msembe and Jongomoro, one near Mdonya, and four in a remote section of the park that is located on a higher elevation plateau which is void of water in the dry season. These aerial photographs will help us determine herd sizes and better understand how the herd sizes are changing over the seasons.

Picture 1: A buffalo herd photographed from the air.


Picture 1: A buffalo herd photographed from the air.

In the afternoon we proceeded to search for the buffalo herds from the ground, and successfully located the herd seen near Mdonya. We were lucky and saw the collared buffalo. She was in great condition and the collar appeared to fit well. We did condition scoring of all visible buffaloes, estimated herd composition, and took notes regarding the vegetation in the area.

Picture 2: Collared buffalo near Mdonya on February 25th.

Picture 2: Collared buffalo near Mdonya on February 25th.

Day 2, Thursday February 26
We went north of Jongomero to locate a large herd with 4 collared buffaloes. On the way from Msembe to Jongomero we listened for one buffalo known to be with a smaller group using a VHF antenna and receiver. This was the group we had not been able to see from the air. We heard a clear signal but she was across the Ruaha River.

North of Jongomero we came very close to the collared animals and heard the VHF signals of all of them. We went off road to see the herd(s), but they kept moving in front of us (based on the many tracks and warm feces). The vegetation was very thick, brushy, and sometimes also muddy, so it was very difficult to drive. We saw a few buffaloes but they were very nervous and ran off into thick bush where we could not follow. We recorded the vegetation types of the area, approximated the herd size and recorded observations of the buffaloes we had seen. On the way back to Msembe we listened for the smaller group again, but she was still across the river. Daniel Mathayo (Ruaha National Park ecologist) said the river was high right now, so she likely would not cross back anytime soon.

Day 3, Friday February 27
From our collar data and the aerial survey we knew that the remaining four collared buffaloes were up on the higher elevation plateau, out of the Rift Valley. A ranger reported that he had seen a buffalo herd near the road to Mpululu (located on the plateau) the night before. We had not planned to drive up onto the plateau since there are only few roads and it gets very muddy after rain. However, the ranger reported that the road to Mpululu was open, so we went up there to try to see the herds.

We heard the VHF signal of 3 of the 4 collared buffaloes at different times and came within 2 km of the last location of one of the buffaloes (logged at 5 am Friday morning). We tried to drive toward the signal but kept running into water or very muddy areas. There were also a lot of thorn bushes, and we had one puncture (asante Erasto for changing the tire).

In the end we found a drier grassy area and managed to drive for a while towards the signals. After a few kilometers we were blocked off by a huge "korongo" (a seasonal waterway) with a 100 feet drop to the bottom. That was the end of it! We still could hear the signals there, but had to turn around.

Picture 3: Challenging wet season driving near Jongomero.

Picture 3: Challenging wet season driving near Jongomero.

We described the vegetation of the area (so we obtained useful information from the adventure) but did not see the animals. We have decent aerial pictures of those herds, so we will still be able to estimate herd size and possibly get some information on herd composition.

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Overall, we accomplished the main goals of the exercise, which was to estimate the wet season herd sizes and understand more about the seasonal habitat preference, but due to the tick vegetation and wet terrain, we were unable to reach all the herds. We are thankful to Ruaha National Park for the great collaboration on this project.

Buffalo, cow, man, and mycobacterium – inside the microbial exchange in Tanzania

-David Wolking

“For a time, all was bountiful in the land, but then drought came. No rain fell for months, and it became drier and drier, hotter and hotter. The stream stopped flowing. The water hole turned first to mud and then to dry, cracked earth.  One by one, the animals slowly left or starved until no one was left…”  - Lion, Chameleon and Chicken, A Gogo Bantu Folktale from Tanzania

Change is coming.  It was first recognized in the landscape, when the Great Ruaha River in Tanzania, the lifeblood of a land where miombo woodlands of Southern Africa blend into the Sudanian Acacia-Commiphora zone of East Africa, slowly dried up.  That seasonal drying, along with other changes in the landscape, agricultural intensification, deforestation, extension of grazing lands into protected areas, may be the source of other less noticeable changes, microscopic changes. 

In the Ruaha ecosystem, home to Tanzania’s largest national park and protected area, researchers with the Health for Animals and Livelihood Improvement (HALI) project are investigating how these changes at both the landscape and microscopic level affect the health of wildlife, domestic animal and human communities.  In a new publication released in June, HALI researchers report the detection of Mycobacterium bovis, a bacterium that can cause tuberculosis in animals and humans, in 8 species of wildlife, including the first detection of M. bovisin 3 new species: Kirk’s Dik Dik, vervet monkeys, and yellow baboons.  In addition, the team detected M. bovis in African buffalo inside Ruaha National Park, the first confirmed buffalo infection in Tanzania. 

“Although we anticipated we might find bovine tuberculosis in species closely related to cattle, like buffalo, the documentation of infection in 8 different species occupying different ecological niches both within and outside wildlife protected areas was unexpected and suggests the existence of a complex wildlife-livestock transmission cycle.”   - Dr. Deana Clifford, founding HALI project coordinator and wildlife veterinarian for the California Department of Fish and Wildlife

The microbial market place

In Ruaha, M. bovis is not a stranger, at least to domestic animals and their caretakers.  There is wide spread bovine tuberculosis (bTB) in cattle in the area, and as a zoonotic pathogen, tuberculosis may also affect human communities.  The HALI team looked at bTB in livestock, and observing the land-use changes in the Ruaha area, hypothesized that tuberculosis was also infecting wildlife populations. Livestock herds frequently share grazing lands, foraging areas, and water holes with wildlife, and as a result may swap microbes and parasites with other species through environmental contamination, or in the case of M. bovis, even through aerosols, through a cough or a sneeze.   

From 2006-2010, HALI worked with game scouts employed by the Community Wildlife Management Areas bordering Ruaha National Park, hunting companies, Park staff, and village networks to obtain tissue samples from hunter-killed, depredated animals (animals killed for causing crop damage in fields), and carcasses.  Two HALI game scouts, Coaster and Shukuru, social network nodes for news of animal deaths, would hear about a kill or a carcass and bicycle out into the bush to collect tissue samples and GPS the location.  Samples were then sent to the project laboratory at the Sokoine University of Agriculture, a center of excellence for molecular diagnostics and tuberculosis detection. 

The team collected tissues from 149 animals of 30 different species, the majority (69%) collected outside protected areas in village lands.  Sokoine University cultured the samples for mycobacterium and used PCR assays to detect M. bovis.  Positive samples were spoligotyped (a technique used to delineate mycobacterium species and distinguish unique strains), and they found that M. bovis isolates from infected wildlife were identical to the strains of M. bovis found in livestock herds.  In an area where human settlements, activities and livestock grazing areas are pushing further and further into wildlife habitat, the animals are trading.  They just don’t know it, and it is possible that this microbial trade could be making them sick.

Although the team’s findings suggest that livestock herds and wildlife are sharing M. bovis, it is not clear who started it.  With M. bovis-infected African buffalo herd inside Ruaha National Park, a herd that encounters livestock rarely, and little to no bovine tuberculosis control among livestock in the area, it is possible M. bovis is maintained in the ecosystem by both wildlife and livestock.  Because the team found M. bovis in wildlife species occupying very different ecological niches, from buffalo to other ungulates like dik diks and impala all the way up the evolutionary chain to our primate cousins vervet monkey and yellow baboon, it appears that M. bovis is settled down and is planning to stay.  Buffalo in particular are a major maintenance host for bovine tuberculosis in Africa, once bTB is established in a free-ranging herd, that herd can sustain infection without repeated trade of M. bovis with other animals like livestock.  In other words, M. bovis becomes a resident, and since buffalo are often preyed on or scavenged by carnivores and other wildlife, the microbe can spillover to other species in the ecosystem, even humans like hunters.  In Tanzania wild meat is usually smoked or roasted, nyama choma, but before you have meat you must have a butcher, and field dressing a carcass without appropriate hygiene and sanitation measures can be a risk for exposure to bTB.

Regulating the exchange?

Now that M. bovis seems to be a microbial resident in both livestock and wildlife in the area, how do you control its spread?  The HALI team identify several management options in the article, but for a pathogen intrinsically linked to multiple species in different ecological niches, these management options require an ecosystem-based approach linking livestock and human health interventions with conservation and development goals. 

  1. The Ruaha River is drying, and if that continues, the health of the entire ecosystem will suffer.  The good news is that continuing and enhancing current conservation efforts to improve hydrologic flow, prevent bank erosion and improve water quality will increase water abundance, allowing more spaces for animals to drink and limiting interspecies contact. 
  2. Ecological restoration and conservation efforts should be expanded to preserve remaining wildlife habitat and help address wildlife forays into village land, farms, and grazing areas.  
  3. The veterinary community can target test of cattle and wildlife for bTB and a range of other diseases in shared grazing lands to identify areas or sites with increased spillover risk, and work to better understand livestock grazing strategies, locations, and sites to improve planning for pasture access and livestock production.  
  4. Finally, and perhaps most critical is improving livelihoods.  Increasing income to rural residents through poverty reduction programs, increased market access, training and education can reduce reliance on natural resources for survival, the driving force behind land use change that may be undermining ecological health and driving M.bovis and other zoonotic disease transmission dynamics.

In this approach, conservation is linked to development – with more water from a flowing river, better grazing opportunities, healthier livestock, and improved livelihoods, the pressure for livestock and wildlife to share resources, interact, and exchange microbes can be reduced, and the animals, along with their caretakers, will not have to slowly leave the water holes until no one is left.

 Read the full article “Tuberculosis infection from wildlife in the Ruaha ecosystem Tanzania: implications for wildlife, domestic animals, and human health” at Epidemiology & Infections, or contact the author, Dr. Deana Clifford (dlclifford@ucdavis.edu)