Page 15 - AWA-41-No.1 issue

DAIRY FARMING

FAO publishes new guidelines

for surveillance of influenza in cattle

ince its emergence over two de-
Scades ago, the highly pathogenic
avian influenza (HPAI) H5N1 virus has
evolved into various clades. Clade
2.3.4.4b, first detected in 2021, has
demonstrated a significant capacity
to infect a wide range of species, in-
cluding wild birds, poultry, and more
recently both terrestrial and marine
mammals, including tigers, bears,
seals, and pet cats and dogs. Detec-
tions in dairy cattle in 2024, along
with cases among farm workers ex-
posed to infected cattle, underscore
the urgent need to strengthen sur-
veillance systems.
“Considering the worldwide spread
of influenza A(H5N1) of clade 2.3.4.4b,
the spillover from birds to cattle (and
likely from cattle to humans) in other
countries is expected,” according to What is known and what to do cluding cattle. If detected, veterinary
FAO’s new publication, Recommen- Some infected animals have severe and health professionals should be
dations for the surveillance of influ- clinical signs and high mortality; prepared to trigger a rapid response,
enza A(H5N1) in cattle – with broader those observed in affected cattle in- tighten risk mitigation measures and
application to other farmed mam- clude decreased milk production, generate evidence to support deci-
mals. sion making and policy.
thickened colostrum-like milk, re-
FAO’s new guidelines follow a previ- duced food intake, lethargy, fever, Basic but effective surveillance sys-
ous technical publication summariz- and dehydration. In some animals, tems begin by encouraging farmers
ing the emerging situation, knowl- however, infection may lead to no to self-report suspected diseases and
edge gaps and recommended risk clinical signs at all making it poten- take advantage of routine veterinar-
management actions, and emphasize tially hard to detect. ian visits to farms. These systems can
the critical role of effective passive Much remains to be understood be expanded through opportunis-
surveillance systems that encourage about the transmission of HPAI H5N1 tic testing during vaccination cam-
reporting of suspected cases from among cattle, but it appears to be paigns, monitoring reports from com-
farmers and veterinarians. Enhanced primarily driven by movements of munity and industry groups about
reporting should be focused on high- infected cattle and potentially by reduced milk production and adopt-
risk areas such as those with dense personnel or equipment shared be- ing risk-based sampling strategies.
poultry or dairy cattle populations or tween farms. Evidence also suggests
migratory bird activity, and consid- spillover events have taken place be- These strategies should consider
eration should be given to tapping tween infected dairy farms and near- factors such as geography, wild bird
into informal sources including mar- by poultry units. Other species have migration patterns, seasonality, ani-
ket price changes, social media and also been affected including cats mal populations, and clinical obser-
community networks. vations throughout the dairy value
and mice, and spillover from poul- chain. In the event that an HPAI H5N1
The guidelines are designed to im- try to pigs has also been seen. Even case in a cow is confirmed, public
prove early detection of spillover if pigs show no signs of disease, they health authorities should be imme-
events and support evidence-based represent a point of concern as pigs diately informed and investigations
disease control measures, aiming to can catalyze genetic reassortment of initiated to determine if farm work-
assist Members to optimize the use avian and human influenza viruses, ers and other close human contacts
of limited resources through lever- potentially creating new strains with have been exposed or infected. For
aging existing surveillance activities pandemic potential. WOAH-listed diseases, cases should
to achieve their surveillance objec- FAO’s recommendations propose be reported using WAHIS and tech-
tives. These recommendations have the minimum surveillance objective nical experts are also encouraged to
broader application to other farmed for all countries ought to be to rapidly submit data to FAO’s Global Animal
livestock species.
detect spillover events of HPAI H5N1 Disease Information System (EM-
from birds to non-avian species, in- PRES-i+). Circle 19 on enquiry card
Vol. 41 No. 1 13