Perfect Creature

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The film opens as a pregnant woman (Danielle Cormack) gives birth to a vampire. A young Brother, Silus, aged 10â13 is told this child, Edgar and he are from the same mother. Throughout this introduction the mother is in visible emotional distress, reaching out across the room to Silus, trying to touch him.
Captioned "100 Years Later." Jamestown slum has had a series of attacks on women, who are all found with their throats bitten. Lilly Squires (Saffron Burrows) is in charge of the human police investigating these cases. She states that she comes from a workhouse in this same slum, and we establish that she is one of the few cops who care what happens to these people at the bottom of the socioeconomic heap. Lilly finds a small boy who witnesses one attack, and tells her that a Brother was responsible. As the police don't want to panic the city, the string of murders is explained away as being the result of an outbreak of the rampant influenza virus.
Silus (Dougray Scott) is detailed by the church cardinals to work with the human police, because the Brothers know that these attacks have been carried out by a Brother; Silus's brother Edgar (Leo Gregory). Edgar has sent Silus a recording of his last murder, challenging him to find and stop him before he kills again. Edgar provides the location of his next murder.
With Silus' help, Lilly puts together a task force to stake out the area Edgar has targeted. However Edgar distracts the cops and attacks Lilly, biting her in the neck. An officer interrupts the attack and Edgar flees. To save Lilly's life, Silus tells her to drink his blood, which she does. Silus then pursues Edgar, managing to shoot him with a tranquilizing dart. Silus later visits Lilly in hospital. We establish that she has no family as they died from influenza. Lilly is having visions from drinking Silus' blood. The newspapers have published a fake story of the death of the killer; a deranged human who believed he was a Brother.
Edgar is being held in a "brace", a spiked body restraint in a cell in the church basement. Because Silus is soon to be made a member of the "inner circle" he is told the full details of what happened to Edgar. The cardinals are worried that not a single Brother has been born for 70 years, and that a female vampire has never been born. Although they have publicly banned genetic research, the church has been carrying it out in secret. Edgar has been developing a virus to inject into pregnant women, to force the baby to be born a vampire. Alas the virus has mutated, and it has turned the women into violent, insane, psychopaths. Ten of Edgar's research subjects are already dead, and the last one is dying. Edgar has also become infected, and is now insane, although the effect is slower due to his strong immune system.
Silus visits Edgar, who vows to escape and finish off Lilly. Edgar accuses Silus of being in love with Lilly, despite Brothers being forbidden to love. The night Silus is at a ceremony in the church for his investiture as a cardinal Edgar escapes, killing the guards and receptionist, and disappears into Jamestown. He enlists the help of a local named Freddy to help him catch Lilly. Edgar has installed a tap and tube system into his forearm, so he can turn on a flow of his own infected blood at any time. He catches a policewoman and fills her mouth with his blood. Freddy insists on getting his own share as well, not knowing it is infected.
Silus is guarding Lilly at her apartment with Lilly's colleague Jones. When she is sleeping Silus shows some affection for her by imagining kissing her. Later, Silus leaves to investigate a noise downstairs and Lilly and Jones patrol around. When Lilly approaches a window, Edgar bursts through from outside and grabs her. Silus and Edgar grapple, however Silus is knocked unconscious long enough for Edgar and Lilly to disappear.
The virus has spread throughout Jamestown. The government has instituted a quarantine, and soldiers shoot anybody who attempts to leave. Humans are rioting outside the churches, and throwing their rosaries back at the Brothers.
Silus discovers Edgar's location is Jamestown's water source. Edgar is dripping his blood into the water supply, infecting all of Jamestown. However, each suburb has its own separate water supply. Silus is determined to go in and rescue Lilly, however another cardinal tells him that Jamestown will be burned to the ground to make sure that the virus dies, and Edgar with it. He warns Silus that his own career will be doomed if he ignores the "greater good" and breaches quarantine.
Silus breaks through into Jamestown and heads to the aquifer, dodging the infected. Lilly is handcuffed to a water pipe in a locked basement. Edgar comes in and she tries to persuade him to stop but instead he challenges her about her dead child, saying that her race is good at abandoning children. Edgar finds Silus and they fight. Just as Silus is winning, Edgar throws him backwards onto the prongs of a steam injector. As Silus lies groaning, and possibly dying, on the ground, Edgar approaches with a portable steam injector. When Edgar depresses the trigger steam comes out. Edgar threatens to burn Silus's face off so that he will be more of a monster just like him. Lilly comes up behind Edgar and kills him by stabbing another steam injector into the back of his skull.
Silus escorts Lilly from the water facility. He kisses Lilly and says she must do something. He gestures to a building then tells Lilly she must look after what she will find in there and keep it away from the Brotherhood. Lilly enters the building, and finds the other Brother, a dead woman, and a baby. The Brother tells Lilly the infant is the first female vampire ever born. The virus has created her and she is truly the first Perfect Creature.
Silus is branded a heretic, and must stay in hiding. Meanwhile, Lilly is caring for the baby and Silus is watching over her. The movie ends with Silus saying that he is being hunted but he will always fight back, leaving scope for a second movie.

Question: What is the killings explained away as?
Answer: influenza virus