March 1955] G. S. RATHORE, P. D. MATHUR AND N. S. SANKARNARAYAN 5
Table I shows that the only place where sheep were free of helminths is Bap,
a teshil of Jaisalmer district. This place has no trees but this teshil is a
widespread plain of good grass. No cultivation is possible as the plain is
practically waterless with a yearly rainfall of about five inches. Tanks or ponds
are often 10 to 20 miles apart. Such tanks are the only source of water supply to
man and animals. The sheep found there are of good size and are the healthiest
so far examined in Rajasthan (Plate I, fig. 1). The shepherds are nomadic but
seldom go out of Jaisalmer district.
The sheep of Udaipur are the poorest specimens and carry the heaviest load
of helminths (up to 4000 ova per gramme of faeces) (Plate I, fig. II). Udaipur
is full of lakes, canals and low valleys. Despite this, pastures are scanty as moist
places are cultivated and dry areas are rocky. The sheep, therefore, are weak
and constantly exposed to worm infestation. Moisture is thus not the only condi-
tion favourable to helminthiasis.
Kotah, a riverine district, has healthier sheep and goats due to good grazing
available, and their condition is far better than others except those of Jaisalmer.
Bikaner district in general is dry but the animals are not free from helminthiasis.
Raisingnagar in Bikaner is a sandy waste recently irrigated by canal and brought
under cultivation. Where land is irrigated it is naturally cultivated with the result
that no pasture lands are available, and the condition of sheep in canal area is not as
good as in the dry areas of south Bikaner.
Ajmer and Jaipur are comparatively dry areas with tolerably good seasonal
pastures. The animals are better than those of Udaipur and Pali (Jodhpur) (Plate I,
fig. I) but poorer than those of Jaisalmer or Bikaner. Nagour area (Jodhpur),
like Bikaner, is quite dry with no grazing and animals there which are very poor
carry a heavy load of worms. The results of this limited survey establish beyond
doubt the widespread incidence of helminthiasis and the causes of its varying
intensity. The map illustrates these points in the different regions of Rajasthan,
including Ajmer State.
The most favourable condition for the spread of helminthiasis is, therefore,
malnutrition due to absence of pastures, and not necessarily water-logging or heavy
moisture, though such conditions may aggravate. This finding has been supported
by Gordon [1948] who, in his lengthy and comprehensive paper presented at the
annual meeting of the Australian Veterinary Association in 1947, describes experi-
ments illustrating the effect of the nutritional plane on resistance in sheep to
Hœmonchus contortus infestation. The Ministry of Agriculture, England, has also
reported a continuous increase in the number of parasites in sheep under grazing
conditions, and that the danger point may be reached at any time as a result of
changes in the nutritional plane or in the weather favourable to parasite develop-
ment.
The causes of helminthiasis can thus be summarised as follows :
(a) Where good grazing exists, animal condition is good enough to ward
off clinical disease.
(b) Poor pastures with water-logged and moist areas are the best for helmin-
thiasis infection.