Quantity of anti-rabies antibodies in 110 dog serum samples determined by comparing the optical density of the sample to a standard curve (>4 EU/ml = high seroconversion level; 0.54 EU/ml = sufficient seroconversion level; 0.1250.5 EU/ml = insufficient seroconversion level; <0.125EU/ml = undetectable seroconversion). expressed as equivalent units per ml (EU/ml). == Findings == Of the total samples, 89.09% exceeded the required seroconversion level ( 0.5 EU/ml); another 9.09% did not reach the seroconversion UNC-1999 level (0.1250.5 EU/ml); and 1.81% had undetectable seroconversion levels (<0.125 EU/ml) suggesting that the animal had not seroconverted according to the PLATELIARABIES II test. Only one factor, the condition under which the dog was kept, was significantly associated with the antibody titer level. No association was found for any of the other factors included in the study. == Interpretation == PYST1 Vaccination is the most effective measure for prevention and control of rabies. The locally manufactured brand of vaccine, which is available in Nepal, is potent enough to generate a sufficient amount of protective antibodies, equal to international brands. == Introduction == Rabies is a vaccine-preventable, viral zoonosis belonging to neglected tropical diseases that can infect all mammals, but over 99% of all human death from rabies are caused by domestic dogs [1]. According to the World Health Organization (WHO), 59,000 people die from this disease yearly, of which 3050% are below 15 years of age. Over 95% of the human rabies cases are concentrated in Asia and Africa, with Asia having 60% of the total number of UNC-1999 cases [2] [3]. Dog bites are the most important cause of human deaths from rabies in those regions [4] [5] [6]. Nepal is a landlocked country between China and India; the latter having the largest UNC-1999 rabies burden in the world [3] [7]. Nepal has an open border with India and the socioeconomic status is quite similar in the two countries. China has the second highest incidence of rabies [8] with an annual 2,000 to 3,000 human deaths, of which more than 95% are due to the bite of a rabid UNC-1999 dog [5]. With the two neighboring countries having a high rabies burden, the disease has become endemic and a priority zoonotic disease in Nepal as well [9]. There, the disease has been confirmed in cattle, buffaloes, goats, alpacas, dogs, and mongooses. Rabies occurs throughout the year, and dogs are the principle vector for the transmission of disease. Unfortunately, the true status of rabies burden due to vectors in Nepal is unknown. There are two primary and interrelated epidemiological cycles of rabies in Nepal. One is the urban cycle which involves domesticated dogs, and the other is the sylvatic cycle which involves wildlife [10]. A study conducted between 1991 and 2000 showed that more than 96% of rabies patients shared a history of rabid dog exposure, indicating that the urban cycle is the main source of human rabies [9]. Large numbers of human rabies cases in Nepal are due to stray and community dogs. Host wise prevalence study also suggests that 61.7% rabies cases were detected in stray and community dogs [11]. Thus, this rabies cycle is maintained by stray and community dogs. Sometimes there is spill-over from stray and community dogs to pet dogs, which further adds to the human rabies burden. Vaccination of dogs is one of the most important preventive measures in areas where dogs are the main source of human infection. For the dog rabies mass vaccination program, achieving a coverage of least 70% appears to be sufficient to prevent transmission rabies to humans for at least 6 years [10,11]. A vaccination rate of 6070% of pet dogs has been shown to result in a drastic decrease in the prevalence of the disease in humans [12]. As vaccination is the primary control measure, it is important to determine the level of anti-rabies antibodies in animals to evaluate the efficacy of the control measures [13]. So far, no studies have been conducted in Nepal to evaluate the efficacy of the vaccines being used, or to determine if the vaccination programs that have been implemented are an effective strategy for the prevention and control of rabies. Various studies have shown that the type of vaccine used, the number.