KARACHI (Reuters) - Widow Hoori Fatima, 76, was still struggling with grief over the death of her son Ali Raza, the familys only breadwinner, in late October. Wiping her tears away with her headscarf, Fatima said her son died of severe gastroenteritis and cold after they fled surging floodwaters in the Tando Allahyar district of Sindh, caused by torrential monsoon rains in August. It rained dogs and cats for several days non-stop, and swathes of lands were flooded, forcing us to move to safer places on higher ground. There was a huge stampede, and hue and cry, she recalled. Like tens of thousands of other families, now I and my children are in a shelter-less camp set up by (NGOs) on the main highway connecting Badin to the northern part of Sindh. At least 466 people died, 756 were injured and over nine million were displaced by this years devastating floods in Sindh province, according to Pakistans National Disaster Management Authority (NDMA). The latest UN report puts the number affected by the floods in Sindh and the southwestern province of Balochistan at a lower figure of more than five million people, adding that nearly 800,000 houses have been damaged, with around 40 percent of them completely destroyed. This years emergency follows on the heels of an even bigger disaster in 2010, when massive flooding affected some 20 million people and destroyed 1.6 million homes from north to south in the South Asian nation. According to Oxfam, around three quarters of those affected by this years floods are still without shelter. Nearly three million are in urgent need of food aid, and two million 500,000 of them children - are at risk of water-borne diseases, malnutrition and hunger, the charity says. Yet despite the scale of need, international NGOs working in flood-hit areas have warned that the post-flood relief operation - reaching over five million people - may have to be closed down because they are running out of funds. Aid groups somber warnings about halting their emergency response have triggered anxiety among Pakistan government circles and local NGOs. But international donors dont seem to be listening. As of Dec. 7, an U.N.-backed appeal for response activities was only 37 percent funded, with $131 million covered out of a total of $357 million requested for work between September 2011 and March 2012. The United States is the largest donor so far, with a contribution of $35 million, followed by the European Commission, Canada, Japan, Germany and Britain. The U.N.s Central Emergency Response Fund has also given a grant of nearly $18 million. GROWING VULNERABILITY TO DISEASE Officials from Oxfam, Save the Children, Care International and ACTED are concerned that the sluggish pace of contributions means they are unable to tend to the mounting miseries of many flood-affected communities. And they do not rule out the possibility of a major humanitarian crisis if donors dont come forward urgently with more money. This is an exceptional situation that the people are facing. Acute shortages of food, water, shelter and sanitation have further weakened peoples - particularly pregnant women and childrens - resistance to diseases, said Neva Khan, Oxfams country director in Pakistan. Oxfam has said it will have to cut back on its relief efforts after December if it does not get further funding and other aid in kind, leaving the 3.9 million people it had planned to reach without help. Save the Children has raised only around a third of its global appeal for the floods, while Care International says it has reached only around 10 percent of the 150,000 people who need emergency healthcare in the areas where it works, due to a serious funding deficit. Meanwhile, more than 60 percent of those in need remain without adequate food, safe drinking water, healthcare and shelter, aid workers say. Many of the displaced are living in extremely unhygienic conditions without access to clean drinking water and basic sanitation facilities. This could lead to outbreaks of water-borne and vector-borne diseases like malaria, typhoid, dysentery, cholera, pneumonia, diarrhea, hepatitis and skin infections. The disease situation may aggravate further and become uncontrollable, said Bharumal Armani, a relief worker for the Society for Conservation and Protection of the Environment (SCOPE) in Sindhs remote southern Tharparkar district. David Wright, Save the Childrens Pakistan country director, warned that at least two million adults and three million children are threatened by disease. We had expected the situation to stabilise by now, but it is going from bad to worse, he said. Each day that passes puts more children at risk of contracting diseases. Malnutrition levels among children under-five are among some of our worst-recorded cases. Childrens immunity is very weak, and we fear winter will make the situation worse if aid is not immediately stepped up. The approaching cold season and stagnant water have intensified the likelihood of a jump in cases of acute respiratory infection and a major outbreak of malaria. Over 160,000 pregnant women will require life-saving medical services in the next six months, aid agencies estimate. 'DISTRESSINGLY UNDERFUNDED Nonetheless, the 2011 floods flash appeal for Pakistan remains distressingly underfunded, Stacey Winston, a spokesperson for the U.N. Office for the Coordination of Humanitarian Affairs (OCHA) in Pakistan, told Reuters. Winston attributed the slow response of rich governments to ongoing global economic woes and competition for funds from other disasters around world. It has been quite hard for them to give money to help Pakistan to cope with the post-flood emergency situation, which will certainly affect UN agencies in providing life-saving clean water, sanitation, food, shelter and healthcare, she said, adding she hopes donors will be able to step up their contributions. The Pakistan government is also struggling with a funding crisis and may have to cut back its relief operations due to rapidly depleting resources. Officials are concerned that the already precarious food system in southern Pakistan is under threat. Many farmers in the region will miss the winter sowing as knee-deep floodwaters are still standing in the fields in most areas, with breaches on waterways unplugged. An estimated 3.6 million people urgently require agricultural support to resume food production and income-generating activities, including cash-for-work programmes that will help rebuild the devastated areas. Over 67 percent of food stocks, 73 percent of crops, and 80 water and sewerage systems have been destroyed in 13 districts of Sindh, according to Zafar Iqbal Qadir, chairman of the National Disaster Management Authority. With winter approaching fast, millions of people, who are still without shelter, will be left out in the cold, he said. Thus, the affectees are now in urgent need to witness the same generosity by the international donor community and giving that took place last year during the climate change-induced floods.