how is the first one different from others?
Unlike other types, in this the red blood cells (erythrocytes) are larger than their normal volume.
Macrocytic anemia
 A macrocytic class of anemia is an "anemia" (defined as blood with an insufficient concentration of hemoglobin) in which the red blood cells (erythrocytes) are larger than their normal volume. 
what is apororhynchus? It a genus of small parasitic spiny-headed  worms. does it cause any disease? Yes, specially in birds. can you name any? Enteritis and anemia. where did it get the name from? The name  was chosen based on the characteristic absence of a proboscis in this species of Acanthocephala. what symptoms does the second disease show? Weakness or fatigue,  poor concentration, shortness of breath on exertion ,increase in  cardiac output.  palpitations, angina , intermittent claudication of the legs, and symptoms of heart failure. how can it be diagnosed? It is typically diagnosed on a complete blood count. what are the different forms of it? Macrocytic anemia, microcytic anemia , and sickle cell anemia.
wiki:2261800
Macrocytic anemia [SEP] Introduction
The term macrocytic is from Greek words meaning "large cell". A macrocytic class of anemia is an "anemia" (defined as blood with an insufficient concentration of hemoglobin) in which the red blood cells (erythrocytes) are larger than their normal volume. The normal erythrocyte volume in humans is about 80 to 100 femtoliters (fL= 10 L). In metric terms the size is given in equivalent cubic micrometers (1 μm = 1 fL). The condition of having erythrocytes which (on average) are too large, is called macrocytosis. In contrast, in microcytic anemia, the erythrocytes are smaller than normal. In a macrocytic anemia, the larger red cells are always associated with insufficient "numbers" of cells and often also insufficient hemoglobin content per cell.