Recent spread of tuberculosis in the Kapiti and Horowhenua districts The Kapiti, Horowhenua and Manawatu dis- proximity to Wellington, there are many Tuberculosis breakdowns tricts have traditionally been free of bovine subdivisions of small farming or lifestyle tuberculosis. lnvestigations of tuberculosis blocks whose owners commute to the The breakdowns that occurred are breakdowns before 1990 showed that the in- capital. Horticultural blocks, with accom- shown in Table I. fection couldgenerally be traced to cattle that panying shelter belts, are scattered be- Otaki Beach: In early 1992, a large had movedfrom tuberculosis endemic areas. tween the livestock farms as the climate town-supply dairy herd just north of the Most breakdowns in cattle herds involved is suitable for many enterprises such as Otaki River (Property A, see Table I) was only a single infected animal. Since 1990, pip and stone fruit. Generally the owners tuberculin tested following the finding outbreaks ofbovine tuberculosis have occurred of smaller 'lifestyle' blocks farm a few of a tuberculous lesion in a bull beef in herds in the Horowhenua and Kapiti Dis- cattle, sheep or horses and the properties animal at slaughter in December 1991. tricts. At the time of these breakdowns there change hands frequently. Thus stock and Investigations revealed no obvious source was no immediate obvious domestic animal human movement is commonplace and of infection. The whole herd test resulted source of infection so a tuberculous wildlife part of the farming culture. in 12 reactors, eight of which had visible source was considered. Subsequent surveys Before 1992, the endemic area to the lesions at slaughter. of wildlife showed that tuberculosis was south,(')included the area around Moon- As usual in this district, there had present in theferret and cat population in the shine Valley and Pauatahanui (Figure 1). been many stock movements from the Otaki Beach area, and in the ferret and pos- This boundary was drawn after persist- herd since the previous whole herd test. sum population around the Manakau town- ent infections in small herds around these Heifershad been grazed at Te Horo Beach ship. localities in the 1970s and the finding of and animals had been bought. However, The Kapiti Coast and Horowhenua tuberculosis in possums, wild deer and investigation of all the source and in- districts of the lower North Island are pigs in 1980. contact herds and immediate testing on intensively farmed areas and extend from However, in 1991 there were several many of these herds revealed no obvious Paraparaumu north to the town of Fox- breakdowns inbeef cattle and dairy herds source of the infection. ton and from the coast eastward to the in the Paekakariki Hill and McKay's Testing of all neighbouring herds re- Tararua mountain ranges. On the eastern Crossing areas that led MAF Quality vealed only one tuberculous animal, a side of these ranges is the Wairarapa, Management (MQM) staff to believe that 15-month beef heifer on Property B. which has been known to be an endemic the feral animals inhabiting the bush this There had been no direct contact be- area for bovine tuberculosis since the far north were infected with bovine tu- tween infected groups on Properties A 1970s, with wild animals such as pos- berculosis. So in 1992 the northern Wel- and B but the infected animals had at sums and red deer infected. lington endemic boundary was redrawn some stage grazed the paddocks adja- The vegetation in the Kapiti and to cross from the coast to the ranges at cent to the beach. High on the list of risk Horowhenua districts is mainly grass Paraparaumu. At the time the placement factors was a feral animal source, so a with some lupin and a few remaining of a tuberculosis 'buffer', in which feral survey was undertaken of possums, fer- boxthorn and pampas bushes on the animal control would be ongoing, was rets and feral cats. coastal sand dunes. There are several raised.") Further information was re- In the area in which the cattle had inland lakes and swamps that supply quired before an effective 'buffer' could grazed, possums were in fairly low num- cover for wild mammalian and bird life. be put in place. Therefore all stock north bers (0.26 possums per hectare) as the Rabbits are controlled regularly as they to the Otaki River, the northern bounda- land supported little of their habitat. Fer- are in abundance, particularly in the coast- ry of the 'fringe' zone,(')were put on to an ret and cat numbers were estimated to be al areas. annual tuberculin testing program. high because of the large numbers of Dairy farms are scattered throughout the area and many are on a winter milk (town) supply contract. Beef breeding and beef finishing make up a significant proportion of the farms. Because of the 25 0 25 50 75 100 Kibmetas Figure 1: Map ofthe south eastern North lsland of New Zealand 18 Surveillance 23(2) 7996 rabbits and birds in the open sand dune Table I: Herds affected with tuberculosis in the Kapiti and Horowhenua districts country and around the lakes and swamps. In the first weekof the survey, a tuber- Date Location Property Herd First Reactors1 M. bovis REA Comments culous ferret was found on the property Type detected No.Tested isolated Type adjacent to Property A. About this time Dec Otaki A Dairy Slaughter 121415 8 W.CP Skin Tb bovine tuberculosis was found in ferrets 1991 Beach also present in the Mackenzie Basin of the South Is- land, on and around properties on which Feb Otaki B Dairy & Testing 11412 1 W.CP bovine tuberculosis was present in the 1992 Beach Beef farmed livestock. (2) The survey contin- Mar Otaki C Dairy Testing 31224 3 Pending ued for several months and moved fur- 1994 Beach ther inland but no evidence of tuberculo- sis was found in the more than 600 pos- May Otaki D Dairy Testing 31482 1 Pending sums examined. 1994 Beach In July 1992, a cat shot in the northern part of the survey area, towards Waikawa APr Pukehou E Beef Testing 2178 2 W.CP Beach, was found to have extensive tu- 1993 Breeding berculous lesions. Although the disease May Pukehou F Deer Testing 191812 1 W.CP Avian had not been found in possums, possum 1993 reactivity in control was instituted on the assumption herd that possums, the traditional tuberculo- sis vector, could be the primary source of Jun Te Horo G Dairy Testing 91394 1 Skin Tb the disease in the other ~pecies.(~)[~)Apart 1990 Beach also present from the ferrets and cats trapped and Dec Te Horo H Dairy Testing 61246 2 W.CP Skin Tb caught at the time of the survey, no fol- 1992 Beach also present low up control has been directed towards ferrets and cats. Aug Te Horo I Dairy Testing 121220 1 Skin Tb The Otaki Beach and Waikawa Beach 1992 Beach also present areas have now been under intensive Nov Te Horo 3 Beef Testing 11103 1 W Animal possum control for two years (see Figure 1993 Beach Breeding bought in 2) and possum numbers in the areas have continued to diminish (1993/94 counts Mar Te Horo K Deer Slaughter Pending 4 Pending 0.134 possums per ha). In March and I994 Beach May 1994 two more dairy herds were placed on Movement Control when tu- Jun Manakau L Beef Slaughter 0117 1 Pending 1993 Drystock berculin test reactors with tuberculous lesions were detected at the annual test. Oct Manakau M Beef Testing 3/25 2 W.CP Both herds are neighbours of the original 1993 Drystock severely infected herd, and the disease had not been detected previously in these Nov Manakau N Dairy Testing 321304 19 W.CP Within herd herds (Properties C and D). 1993 infection also feral source Pukehou: In February 1993, a ferret handed to the Levin Livestock Officer Nov Manakau 0 Beef Testing 1/74 1 W.CP (LO) by a farmer was found to have a 1993 tuberculosis-like lesion in the prescapu- lar lymph node. The ferret had been Jun Manakau P Dairy Testing 6/56 5 Pending picked up on the main road at Pukehou, 1994 near the Forest Lakes turn off, in Novem- Jul Manakau Q Dairy Testing 11252 1 Pending ber 1992, placed in a deep freeze and 1994 retrieved when the LO visited the farm. Histological examination showed lesions Jul Manakau R Dairy Testing 3/21 1 1 Pending consistent with bovine tuberculosis but 1994 Mycobacterium bovis was not cultured. Ma Koputaroa S Beef Testing 2110 12 Pending All animals About a month later at the routine 1976 Breed & with lesions tuberculin test on two nearby farms on to Dry stock bought in the western side of Highway 1, several Mar 1991 reactors were detected and lesions were found at slaughter. They included an Dec Koputaroa T Beef Slaughter 01357 1 Pending aged hind from a nearby deer herd, and 1990 Breeding two bovine weaners in an adjacent small Dec Koputaroa U Deer Slaughter 711012 3 Pending Owner buys beef breeding herd (Properties E and F). I990 in and M. bovis was cultured from the lesions finishes stock from all three animals. Neither herd had a history of the disease, and both had Mar Waitarere V Dairy Testing 11142 1 W.Wait been tested a year previously. These facts, 1992 together with the finding of the tubercu- Jul Waitarere W Beef Testing 1/38 1 W.Wait lous ferret only about 1 kilometer away, 1992 Breeding again indicated that feral animals were a likely source of the infection. Jun Koputaroa X Beef Testing 21383 1 W.Koput TeHoro Beach: In 1YY2, bovine tuber- 1993 Breeding culosis was detected in two large neigh- bouring dairy herds in the Te Horo Beach Mar Koputaroa Y Beef Slaughter 1I540 1 CNI 1994 Drystock area, south of the Otaki river (Properties H and I).