Research Results - (PDF, 101 mb) - USAID

viral proteins are required for further progress
toward development of a serological test for
carriers of the virus and eventually a vaccine to
prevent infections. Problems encountered in
attempts to amplify OPC DNA have now been
resolved and the project is preparing to try this
approach again. Evidence has been obtained
that a relationship exists between the OPC
retrovirus and other type D retroviruses. This
has permitted generation of probes and reagents
that can be used to isolate and identify the cause
of OPC. The project is thus wellprepared to
successfully isolate and propagate the OPC
retrovirus or its relevant genes for use in prepa-
ration of diagnostic or immunoproplactic products.
The second subproject investigated the
protection of neonatal alpacas and lambs against
enterotoxemia by vaccination of their dams with
C.perfringensenterotoxin, and the identification
of colonization antigens on E.coli isolated from
cases of neonatal alpaca diarrhea. Enteritis is
the major cause of death of young alpacas and
lambs. Clostridiumperfringenstype A
enterotoxemia has been established as the main
cause of enteritis, and development and use of a
toxoid vaccine has been purported as the best
means for preventing enterotoxemia.
Vaccines are on hand to conduct vaccination
trials of pregnant alpacas of the South
American Unit in the Veterinary School, University
of San Marcos. An earlier study in Cuzco
could not be concluded due to local political
interference. Anti-enterotoxin antibodies have
been detected from the previous vaccination
study. The results will be published under the
title "C. perfringensenterotoxin toxoid induces
humoral immunity in alpacas."
Immunological evidence was obtained
that, in enterotoxemic llamas, C. perffingens
enterotoxin is absorbed from the intestinal
lumen to the bloodstream and then released
from the bloodstream to the peritoneal cavity,
These results are of vital importance for understanding
the mechanism of pathogenesis, and to
confirm the diagnosis of C.perfingens
enterotoxemia in llamas and alpacas. Another
significant accomplishment of this subproject
72
was the identification of the pili on about 20% of
the E.coli isolates from diarrheic alpacas.
Field studies were concluded on sheep
respiratory disease control and epidemiology of
bacterial and parasitic causes of newborn mortality
of alpacas. During the past eight years,
extensive field studies have been conducted in
Peru to discover the causes, improve the diagnosis,
and evaluate control strategies for chronic
viral respiratory diseases of adult sheep. In this
final year, the goal was to complete baseline
studies which will facilitate future field testing
of diagnostic tests and vaccine products.
The occurrence of ovine pulmonary
carcinoma has been progressively decreasing in
the experimental flocks at the SAIS Tupac
Amaru. The rapid periodic elimination of all
animals from the experimental flocks appears to
result in decreased OPC losses. The offspring
from these less-affected experimental flocks are
being used to repopulate other flocks in the
research unit. This is a means by which the
producer can reduce OPC-associated losses.
Concluding studie.s on epidemiology of
bacterial and parasitic causes of newborn mortality
of alpaca investigated the correlation of
death with nursing, the causes of death, and
characterization of bacterial agents associated
with pulmonary diseases. The importance of
passively transferred immunoglobulin in neonatal
mortality of newborn alpaca cria was verified
in community herds as well as large enterprise
herds. It is now imperative to investigate the
nutritional and management failure of passive
transfer and to study the role of novel bacterial
agents in diseases of crias.
Many improvements were made during
the last year in the capacity of San Marcos
University and IVITA to perform research and
teaching. A masters degree program in Veterinary
Science has been developed and a biweekly
seminar program initiated to disseminate recent
research results. Teaching facilities and computer
capabilities have been improved. Some of
the laboratories have been partially remodeled
to improve research and diagnostic efficiency.